I had the same trouble earlier this year and never found one. Let me know if you have any luck.
I also had difficulty with the first scenario. It seemed to me the units on the top of the map could move right over the victory line uncontested. I had heard there was a fix for this, but never tracked it down. If you happen to find a solution to that, please let me know!
I'll send you an email if I find a VASSAL mod for SP1. Do you mean you had difficulty with the first scenario of SP1 in that the Germans couldn't hold?