I'm facing now another phys related problem.

I have a mesh from which I want to create a phys and an actor. the problem is this mesh is way too big and I need to scale it. how can I scale an actor? do I have to scale it in mesh editor?

you can't dynamically scale an actor,
you can create a smaller actor during creation (there should be scale paramter in the 'create' method)

but I suggest scaling the mesh/phys in the Mesh Editor (slightly more performance increase when phys bodies don't need to be rescaled)

ok thanks I'll try this out!