Forgive the breach in protocol, but I'm on my phone ao quoting is hard.

Anyway, how would the timing work out in the following situation:

I have a character with Darkness Within next to a dude with Empower. Dude only has this power for one click. The first guy attacks, triggers the feat, and deals the damage to his bud.

Is there any trick to the timing that would allow +2 damage?

Because Darkness Within deals damage to the character before making the attack, his dial will change, so he won't be able to use empower on the attack.

However, if the character you're dealing the damage to has empower mid-dial, you could use darkness within to push him onto the empower click and double up the damage bonuses that way.