To my knowledge, you can't soft-cap everything, but you can soft-cap S/L and Melee. There are some who argue that just capping S/L and then focussing on getting E/N up as much as possible is superior to worrying about capping Melee. Doing this, I was able to get to about 38% E/N with a capped S/L.
You'll need to take the old standbys: tough/weave/manuevers/combat jumping, as well as the two 3% defense procs.
You may also want to reconsider the pyre epic pool. Fire/fire is plenty of damage by itself, and you'll probably want something to supplement your endurance instead.
Good luck!
Ardenghast
I've been playing about with Mids and could not get anywhere near but is it possible to softcap (45% version) on a fire/fire/pyre brute.
I don't want to farm but I think one of these could be fun with the right amount of defense.