[Chimera-users] place fragment (again)

Dear all, We are trying to place a fragment in an exact position. We created a fragment with tetrahedral symmetry and we are trying to link an atom of other molecule at 2.00 A of the central atom of the new fragment and making a certain angle (120 degrees for example) with one of the substituents to get the correct orientation of the new fragment. Has anybody an idea that how can we do that? Thanks.