I had used the pack of Khurasan Miniatures partisan pack (ttc-1401) for the door gunners.
Step 1: Remove pintel mount for the miniature figures.
Step 2: Use a pin-vise a hole in the base of the gun mount. I had used a .032 bit with a .031 brass wire. Glue long brass wire into gun mount on the miniature(s).
Step 3: remove the original beam ball turret and cut the armature from the ball turret hinge.
Step 4: pin vise the armature to allow the door gunner's weapon to fit within. Slip the door gunner's brass rod through the armature and snip off the remainder from bottom of armature.
Step 5: file the cut end of he brass wire to allow it to pass through the armature without too much effort.
Step 6: Glue pins into miniatures
Step 7: Paint and enjoy