ratz@ you need to register object as a PH_RIGID, then make it sleep via pXent_setsleep.
And then, add a hinge that you need to it (please read the manual for hinge information).
And at the end, if you'll need to rotate it, add angular forces via pXent_setangvelocity!

Edit: don't try to use PH_POLY for PH_RIGID, it will work only with static geometry! Use CONVEX instead!