Try the new version 2.0! I found a problem between the limits on lean angles and the limits of instability while leaning in the bike. Basically, some bikes was possible to lean to 54º while it's max instability was in 50º and others this instability was in 56º... Thats made some bikes to be much more stable at high angles than others, maybe you using a bike with this problem...
I've tried to do what you saying in the 2.0 and is possible to use a little braking at high angles, but just a little, in terms of that graphical telemetry of the game, something about 10~15%, you can have an idea how to use the brakes here:
I don't know how do you control the bike (keyboard or joypad) but this mod is only enjoyable with a decent joypad, i have a XBOX360 Controller, and i use a trigger as the brakes, to be capable to have a good control of the brake...
If you want, tell here the bike, track and the control settings that you are using to i see if is a problem or is just the way that you are playing...