Yes, if you have your own C/C++ code and want Vizard to execute it, that's very straightforward and relatively easy if you have a C compiler. The method is to buld a compiled Python module (DLL) that you "import" just as if it were a .py module. There's very accessible docs on how to "extend" the Python language on the Python website:
http://docs.python.org/ext/ext.html
If you get stuck on this feel free to ask further.