You should still have gravity on your side. It looks like you've got the trap pointed down on the lower corner of the housing, just out of sight on the bottom of it, right?
I run a Donaldson 15"x8" cylindrical housing in my rig and I know the dust trap still works well. I've got a rubber pipe end clamped over where the "chisel" style trap is supposed to go. I recently removed the assembly to check on the filter and found the dust trap completely packed with dust that had spun out. The filter was almost completely clean (probably would have been if I hadn't let the trap fill up...)