Prada, seriously look into Questran (colestyramine).
It is a bile acid sequestrant. I'm not certain if you actually had any operations, but it is a common problem for people with both UC/Crohn's to have issues dealing with bile acid accumulation - which thus causes loose/watery bowel movements. Pretty simple medicine with little to no sides.
Good job on steaming the vegetables. That would have been my main recommendation. Raw veggies tore me up.
As for the meals, I actually transitioned to a pseudo-warrior diet. One large dinner meal and small snacks throughout the day - or one large dinner and 2 pulses (incidentally the pulse feast that CT released matches this closely). Basically I get the bulk of my food digesting through the night, which helps with frequency and other issues.
The other thing that helped me was that I gave up drinking non lactose free milk and caffeinated beverages. That was tough but it helped a lot. The digestive tract is very sensitive to caffeine, so it may be worth a shot for you.