If you "y'them there is no way to not have rudder trim effect steering trim. You use two channels with a program mix. I suggest you call Horizon product support an have them talk you thru setting up a program mix. They have some very knowledgeable and helpfull tech support guys. I called them just a couple of days ago for a similar programming issue that I couldnt figure out. He knew instantly how to do it and had me taken care of in no time.