direct x matrices

RE EDITED WHOLE POST:

ok so let me revise my question. I have a mesh that is a square:

Code:

Mesh pmesh = Mesh.Box(device, 50, 50, 50);

And I have a matrix that I got from the physics engine I am "porting" over to .net. With that matrix I am suposed to apply it to the mesh (so it rotates and stuff correctly) and than draw the mesh.

I got all but applying the matrix to the mesh? So if anyone has any idea on how to do that, it would be great!

And I also think this is more of a game post now.