First, there is more than one model of TRX 250 in '04, if you could, specify what it is exactly so we can add that info to the thread title. They all use the same rear axle and brake assembly though. Also, I removed one of your threads, please post your question only one time in the forum.
Before I start, I would recommend buying a repair manual and following the instructions in there before following my instructions, because I am just guessing. I am not sure what you mean by "hub" when you say you have it torn down to the hub. To me, that means you took the wheel off, but I assume you did more than that. I will just start at the beginning.
Take off the rear wheel and hub that are on the brake side, I believe that is the right hand side but I am not sure. Remove the arm, spring and everything else that sits on the brake cam outside the cover. Pull off the seal that is in the cover around the axle. Behind the seal you will see a c-clip, remove it. At this point, you should be able to unbolt the cover and pull the cover off, there is a bearing in the cover so you will need to pull it straight as you pull it off the axle. Depending on what the bearing fits tighter to, the axle or the cover, you may be able to separate them by pushing the cover back toward the drum after moving it out a couple of inches. The bearing may come out of the cover, that may make it easier to get the cover off. My guess is that the shoes are mounted to the back side of the cover, you should be able to remove the springs and pull the shoes right off.
Yours truly, sincerelly, love always, Josh aka The DirtDemon.