diff --git a/c++/carla-backend/carla_engine.cpp b/c++/carla-backend/carla_engine.cpp
index a73298b..65fdac9 100644
--- a/c++/carla-backend/carla_engine.cpp
+++ b/c++/carla-backend/carla_engine.cpp
@@ -569,7 +569,7 @@ void CarlaEngine::setOscBridgeData(const CarlaOscData* const oscData)
 // -----------------------------------------------------------------------
 // protected calls
 
-void CarlaEngine::bufferSizeChanged(uint32_t newBufferSize)
+void CarlaEngine::bufferSizeChanged(const uint32_t newBufferSize)
 {
     qDebug("CarlaEngine::bufferSizeChanged(%i)", newBufferSize);
 
@@ -585,12 +585,11 @@ void CarlaEngine::bufferSizeChanged(uint32_t newBufferSize)
 // -------------------------------------------------------------------------------------------------------------------
 // Carla Engine Client
 
-CarlaEngineClient::CarlaEngineClient(const CarlaEngineType& type_, const CarlaEngineClientNativeHandle& handle_)
-    : type(type_),
-      handle(handle_)
+CarlaEngineClient::CarlaEngineClient(const CarlaEngineClientNativeHandle& handle_)
+    : handle(handle_)
 {
     qDebug("CarlaEngineClient::CarlaEngineClient()");
-    CARLA_ASSERT(type != CarlaEngineTypeNull);
+    CARLA_ASSERT(handle.type != CarlaEngineTypeNull);
 
     m_active = false;
 }
@@ -681,11 +680,11 @@ bool CarlaEngineClient::isOk() const
 #endif
     {
 #ifdef CARLA_ENGINE_JACK
-        if (type == CarlaEngineTypeJack)
+        if (handle.type == CarlaEngineTypeJack)
             return bool(handle.jackClient);
 #endif
 #ifdef CARLA_ENGINE_RTAUDIO
-        if (type == CarlaEngineTypeRtAudio)
+        if (handle.type == CarlaEngineTypeRtAudio)
             return bool(handle.rtAudioPtr);
 #endif
     }
@@ -695,7 +694,7 @@ bool CarlaEngineClient::isOk() const
 
 const CarlaEngineBasePort* CarlaEngineClient::addPort(const CarlaEnginePortType portType, const char* const name, const bool isInput)
 {
-    qDebug("CarlaEngineClient::addPort(%i, \"%s\", %s)", type, name, bool2str(isInput));
+    qDebug("CarlaEngineClient::addPort(%i, \"%s\", %s)", portType, name, bool2str(isInput));
 
     CarlaEnginePortNativeHandle portHandle;
 #ifdef CARLA_ENGINE_JACK
@@ -707,7 +706,7 @@ const CarlaEngineBasePort* CarlaEngineClient::addPort(const CarlaEnginePortType
 #endif
     {
 #ifdef CARLA_ENGINE_JACK
-        if (type == CarlaEngineTypeJack)
+        if (handle.type == CarlaEngineTypeJack)
         {
             switch (portType)
             {
@@ -723,7 +722,7 @@ const CarlaEngineBasePort* CarlaEngineClient::addPort(const CarlaEnginePortType
 #endif
 
 #ifdef CARLA_ENGINE_RTAUDIO
-        if (type == CarlaEngineTypeRtAudio)
+        if (handle.type == CarlaEngineTypeRtAudio)
         {
             // TODO
         }
@@ -740,7 +739,7 @@ const CarlaEngineBasePort* CarlaEngineClient::addPort(const CarlaEnginePortType
         return new CarlaEngineMidiPort(portHandle, isInput);
     }
 
-    qCritical("CarlaEngineClient::addPort(%i, \"%s\", %s) - invalid type", type, name, bool2str(isInput));
+    qCritical("CarlaEngineClient::addPort(%i, \"%s\", %s) - invalid type", portType, name, bool2str(isInput));
     return nullptr;
 }
 
diff --git a/c++/carla-backend/carla_engine.h b/c++/carla-backend/carla_engine.h
index 1e28cab..a14a734 100644
--- a/c++/carla-backend/carla_engine.h
+++ b/c++/carla-backend/carla_engine.h
@@ -52,7 +52,9 @@ const uint32_t CarlaEngineTimeBBT = 0x1;
 enum CarlaEngineType {
     CarlaEngineTypeNull,
     CarlaEngineTypeJack,
-    CarlaEngineTypeRtAudio
+    CarlaEngineTypeRtAudio,
+    CarlaEngineTypePluginLv2,
+    CarlaEngineTypePluginVst
 };
 
 enum CarlaEnginePortType {
@@ -96,7 +98,7 @@ struct CarlaEngineMidiEvent {
           size(0),
           data{0} {}
       #else
-          size(0) { memset(data, 0, sizeof(uint8_t)*4); }
+          size(0) { data[0] = data[1] = data[2] = data[3] = 0; }
       #endif
 };
 
@@ -136,6 +138,7 @@ struct CarlaTimeInfo {
 };
 
 struct CarlaEngineClientNativeHandle {
+    CarlaEngineType type;
 #ifdef CARLA_ENGINE_JACK
     jack_client_t* jackClient;
 #endif
@@ -145,6 +148,7 @@ struct CarlaEngineClientNativeHandle {
 
     CarlaEngineClientNativeHandle()
     {
+        type = CarlaEngineTypeNull;
 #ifdef CARLA_ENGINE_JACK
         jackClient = nullptr;
 #endif
@@ -374,7 +378,7 @@ protected:
     double   sampleRate;
     CarlaTimeInfo timeInfo;
 
-    void bufferSizeChanged(uint32_t newBufferSize);
+    void bufferSizeChanged(const uint32_t newBufferSize);
 
 private:
     CarlaCheckThread m_checkThread;
@@ -404,7 +408,7 @@ private:
 class CarlaEngineClient
 {
 public:
-    CarlaEngineClient(const CarlaEngineType& type, const CarlaEngineClientNativeHandle& handle);
+    CarlaEngineClient(const CarlaEngineClientNativeHandle& handle);
     ~CarlaEngineClient();
 
     void activate();
@@ -417,7 +421,6 @@ public:
 
 private:
     bool m_active;
-    const CarlaEngineType type;
     const CarlaEngineClientNativeHandle handle;
 };
 
@@ -489,7 +492,6 @@ public:
     bool init(const char* const clientName);
     bool close();
 
-    bool isOnAudioThread();
     bool isOffline();
     bool isRunning();
 
diff --git a/c++/carla-backend/carla_engine_jack.cpp b/c++/carla-backend/carla_engine_jack.cpp
index eecab37..4fc2bca 100644
--- a/c++/carla-backend/carla_engine_jack.cpp
+++ b/c++/carla-backend/carla_engine_jack.cpp
@@ -227,6 +227,7 @@ bool CarlaEngineJack::isRunning()
 CarlaEngineClient* CarlaEngineJack::addClient(CarlaPlugin* const plugin)
 {
     CarlaEngineClientNativeHandle handle;
+    handle.type = type;
 
 #ifndef BUILD_BRIDGE
     if (carlaOptions.processMode == PROCESS_MODE_SINGLE_CLIENT)
@@ -243,7 +244,7 @@ CarlaEngineClient* CarlaEngineJack::addClient(CarlaPlugin* const plugin)
     //{
     //}
 
-    return new CarlaEngineClient(CarlaEngineTypeJack, handle);
+    return new CarlaEngineClient(handle);
 }
 
 // -------------------------------------------------------------------------------------------------------------------
diff --git a/c++/carla-backend/carla_engine_rtaudio.cpp b/c++/carla-backend/carla_engine_rtaudio.cpp
index 1408819..536a824 100644
--- a/c++/carla-backend/carla_engine_rtaudio.cpp
+++ b/c++/carla-backend/carla_engine_rtaudio.cpp
@@ -143,6 +143,7 @@ bool CarlaEngineRtAudio::isRunning()
 CarlaEngineClient* CarlaEngineRtAudio::addClient(CarlaPlugin* const plugin)
 {
     CarlaEngineClientNativeHandle handle;
+    handle.type = type;
 
 //    unsigned int rtBufferFrames = getBufferSize();
 
@@ -163,7 +164,7 @@ CarlaEngineClient* CarlaEngineRtAudio::addClient(CarlaPlugin* const plugin)
 //        return false;
 //    }
 
-    return new CarlaEngineClient(CarlaEngineTypeRtAudio, handle);
+    return new CarlaEngineClient(handle);
     Q_UNUSED(plugin);
 }
 
diff --git a/c++/carla-backend/qtcreator/carla-backend.pro b/c++/carla-backend/qtcreator/carla-backend.pro
index e778f22..185a9cb 100644
--- a/c++/carla-backend/qtcreator/carla-backend.pro
+++ b/c++/carla-backend/qtcreator/carla-backend.pro
@@ -15,7 +15,7 @@ VERSION  = 0.5.0
 
 SOURCES  = \
     ../carla_backend_standalone.cpp \
-#    ../carla_backend_lv2.cpp \
+    ../carla_backend_vst.cpp \
     ../carla_bridge.cpp \
     ../carla_engine.cpp \
     ../carla_engine_jack.cpp \
@@ -73,6 +73,7 @@ DEFINES += DEBUG NDEBUG
 DEFINES += CARLA_ENGINE_JACK
 DEFINES += CARLA_ENGINE_RTAUDIO HAVE_GETTIMEOFDAY __LINUX_ALSA__ __LINUX_ALSASEQ__ __LINUX_PULSE__ __RTAUDIO_DEBUG__ __RTMIDI_DEBUG__
 DEFINES += CARLA_ENGINE_LV2
+DEFINES += CARLA_ENGINE_VST
 DEFINES += HAVE_SUIL
 DEFINES += WANT_LADSPA WANT_DSSI WANT_LV2 WANT_VST
 DEFINES += WANT_FLUIDSYNTH WANT_LINUXSAMPLER