Hi! i'm sorry to bother, but i still have some problems.
Using just the modelview matrix works fine when the video background is active. In fact, when using the smartglasses in see-through mode, Vuforia applies a projection matrix (retrieved after a per-user calibration process) to correctly display a virtual object on the scene, so that the viewer sees it on the marker, like if it was real.
So, i'm trying to use the same projection matrix on JPCT, and, by forcing it touse the same near and far planes as Vuforia, i am able to see the object right over the marker.
However, the rotations of the object are messed up: it's like I'm seeing it from an arbitrary direction, and (for example) when I rotate the marker clockwise, the object rotates counterclockwise. Maybe it is related to the different reference frame used by OpenGL and JPCT. I tried performing a rotation of the final modelviewprojection matrix (namely the product of modelview and projection mats) about 90 deg about x-axis and a negative scaling on the z-axis, but it has the same problem.
Any ideas?