Thank you for your message. Currently we do not support code engineering on Qt. I’ve forwarded your message to our engineers to follow-up and to investigate the feasibility on supporting it.
In the meantime, I suggest you can try to use our plug-in architecture for working on the Qt source code. Our plug-in architecture allows you to access all the models inside the project so you can create your own plug-in for generating the Qt source code and translate the code back to diagram. For more information about the plug-in architecture, please visit http://www.visual-paradigm.com/documentation/#extend
If you have any further questions, please feel free to contact us again.