Okey Dokey guys, this is how I did it.
Start a Quick Combat, hit pause and escape, that will give you the pull down menu. Select Controls from the pull down and that will open the Controls Settings Menu.
I the Event Category window, select All Commands, then scroll down the list to "Mixture 1 Axis" (this is not available in the engine commands list). Click on Mixture 1 Axis and that will light up the Add Assignment button. When you hit Add Assignment another window will open up asking you to select a button (or some such thing) just move the slider and it will pop up in the little box if available. Hit save and that box will close.
Then in the Event Category window you must click Save the Configuration. You do this in the top window by selecting "Mine" I believe that is one of three choices, the others being CFS3 and Flight Simulator.
This is what I use for all my commands on the X52, I do not use the software that came with the stick.
Good Luck
Beard