Sonar X3 V-Vocal problem with software synths

I have a problem with V-Vocal in Sonar X3. If I have only audio tracks and MIDI tracks for external MIDI devices V-V works fine. But if there's software synths in project V-V won't work anymore. It opens empty or it crashes Sonar totally. It doesn't matter which software synth there is.
 
V-V works fine with Sonar X2 even there's software synths in project.