MS Access Visual Basic support in Kexi. Short story: there's no support.
The reasoning, from the economical to the technical aspect is provided on the KDE Forum.
Or maybe there is some tiny support.
If you look closer, those that in the ancient days called themselves VB/VBA developers can find quite a few similar concepts in Kexi, regarding the object model and the way how the scripting language works. So switching to a new tool does not mean dropping all the knowledge and proper habits.