hmm this one looks fun but the fact remains he STILL rolls on the table and gets thus chosen power but the fact of the matter is if its a shooting attack it counts as if you were in assualt (frazzle and zzap become power weapon attacks)
well you say they cant assualt the unit can still be assualted
i would also imagine if you teleport they will still teleport and perhaps remain pinned? just in a new position.
so summary is you still roll on the chart but a 1, 2, 3 roll counts as a power weapon for that turn
hope thats clear enough and helps in any way ...?