i am having some basic issues with Vector3 conversion... i'm using Monogame and i have a gamemodel class which contains the position, rotation and scaling of the gamemodel but now when i try to import the explosion (demo sample script) i have to switch constantly between different versions of Vector3
This can be mitigated a little by putting casts for the XNA/monogame types into the BEPUutilities types. It does introduce some overhead so it should be avoided in extremely tight loops, but it usually works well enough. An example of a custom expliict cast can be found
here. Implicit casts would work too, and would avoid some typing.
and in my player script when i try to recreate the explosion script i get nothing... no "jumps" or anything, i should also mention i have created a simple jump in my player scripts Update function where i have replaced the position.Y (position in this case is from Xna.framework, NOT BEPUutilities!) out with Explode() to test it out
I'm not sure what you mean here, but here's a couple of guesses:
1) If you're using the BEPUphysics CharacterController type, its constraints will try to keep it from moving due to external impulses. To make a character move, the impulse needs to be large enough or the character needs to have its constraints forcefully disabled (e.g. force it to have no traction, or to jump).
2) If you're manually controlling the position of objects by e.g. setting the y component of the position every frame, the physical simulation will be unable to proceed correctly. Explosions won't cause any vertical movement because the position is being reset continuously.
(have been "using" JitterPhysics until yesterday, which i didn't really use either because of my lack of understanding 
) i hope there is a person in here who can help me out because i have no experience with BEPU and i actually really would like to use it in my game engine 