With my Warrior I enchanted his 2H weapon with ST for one second and it works fine but I'm curious to know if DW with a ST enchantment for one second would work too? Would you need just one weapon with the enchantment and if so equiped in which hand or both enchanted?

I should add that I mean using the dual power attack combo, i.e. holding both triggers (360) at the same time, obviously if you only attacked with one of the weapons (the one that's enchanted) and killed the opponent then you'd trap their soul.

Hm. Don't know for sure, I assume it works. You could just save the game, enchant a 1-H weapon with 1-sec Soul Trap, try it, then either continue or reload.

The power attacks do have one weapon hit before the other one. If the non-ST enchanted weapon hits first and one shots the monster, you will not trap the soul.

I don't think the final blow has anything to do with the use of your weapon. The creature just has to die, not necessarily by your weapon, within the set time. Just tag it with your weapon and finish it off however you like. I tagged them and then spell cast them to dead.

It's quite simple; if you kill the mob after hitting him with that enchanted weapon, OR with the other withing that second, then you get the soul. It works, I've tryed it. Dual power attack works too.