Maybe you recieved my reply, for me it seemed to vanish in bitspace, so here is my answer:
You have to define LAND-PT's when working with vinka spacecraft, or touchdownpoints when making a vessel in orbitersdk and oversize the mass, 10000 i.s.o. 185 and 10000 kf fuel. I first made this as vinka spacecraft and it seemed to work, for 1 session, thereafter never again. So I made a vessel in orbitersdk in c++ and compiled it. That worked.
This seems a lot of work when you don't know how, but luckily I remembered kev33 or kevin shanow makes al kinds of vehicles, witth the source included. So |I went looking in OH and finaly found this beauty: K-car-v2, a lotus-1 racing car, I think. Took it to columbia hills and drove around with 80 mph, rocksteady, in meshland terms. With the help of orbitersdk reference guide I found my way.
I have the sourcecode included in the orbitersdk\source\mer-2003 submap of orbiter.