Bert,
Download the project, and open up VBAIDE and have a look. What I tried to do is pattern it after the way ODCL interacted with AutoLISP: There are only two things going on: functions that control the form (dialog) and 4 functions that interact with AutoLISP: SendCommand (command . . .), EvalLispExpression (myLisp), SetLispVar (setq myVar value), and getLispVar 'myVar. Once you get your head around the logic of VB(A) it really is very easy. It took me a little bit to get comfortable (last weekend) and now I'm delving into the WinAPI. I'm planning on converting as much as makes sense over to straight VBA as time allows.
The best way I learn is to dive in and start codeing - give it a whirl!
jb