Sparrow-5

I'm having problems trimming the hornet in flight when it comes to trimming it on the roll axis, pitch axis works. I have tried Ctrr+ left/right arrow keys, Input for joystick etc. as well holding them down for a longer period in case the whole trimming happens slowly but without any result. The values on the FCS page changes when i put the input in but as soon as i let go of the trim the values resets to the values before i started to try and trim the aircrafts roll axis.