DD, if you use butterfly/crow/airbrake ,then your flaps can easily be moved on the throttle stick.

Your channel 6 dial is setup to only move the channel 6 servo. you can turn it off as listed above.

to put the flaps on a switch, do an offset mix(master OFST) slave flaps, link ON, and assign to your desired switch.

If you look at the FAQ for the ultrastick it will tell you how to do this type of setup in acro mode, it should be helpful in clarifying things for you.