Wow, good on you for getting along for so long eating raw fruits and veggies with no troubles!
Mushrooms and corn are the biggies. Raw carrots can also be an issue in larger quantities. I've heard cabbage can be a culprit as well.
I only worked up the nerve to eat raw salad greens (including tougher ones like kale) with my end ileo, nothing else raw. Maybe you could try blanching? Still raw-ish but probably a lot more digestible.
dx'ed UC pancolitis 5/12
past meds: asacol hd, VSL#3, apriso, rowasa, xifaxan, 6mp, cortifoam, pentasa, cimzia, canasa, butyrate, flagyl, cipro, prednisone, remicade, methotrexate, cholestyramine, cortenema
current meds: none!
step one: colectomy, end ileo 1/16/13
step two: j-pouch construction, loop ileo 5/1/13
step three: takedown sometime