In ME3, the only armoured enemies are also big. Brute, Banshee and Atlas. They have DR85 odd, which makes most weapons outright useless (think DR20 in MC terms). You could go as easy as "you add your DR to this opposed check" for things like throw / pull etc (so that players in Riot Gear type stuff are pretty resistant to all forms of attack, but are slow and have minimal Defence) or simply handwave it as "It's not armour that stops the powers, it's bulk - you just can't singularity a Brute".
I'd go with the latter, because trying to replicate that level of videogame mechanics at the tabletop adding unnecessary difficulty and changing the core tabletop mechanics too much to be worth the benefit. Like I said in the Shadowrun thread, capturing the flavour is more important here (especially when the reason for Armour stopping powers is to attempt to built a Rock-Paper-Scissors balance point in their game, so Adepts don't rule the roost*).
*Yes they failed, due to Warp-Throw being able to tear anything apart faster then any other option in the game, but the idea was balance.