a lil different then Chad's......

First hold menu and turn power on, under code 17: Devise Select inhibit Aux 3 (or your channel of your choice) exit code 17 back to menu.
Next enter code 22: Wing Type, the Duel feature of Ailerons to Aux 3 (or the channel you selected above) and exit out of the menu and press menu again to exit out to the normal mode (or cycle the power switch).
Press menu and enter into code 51: Programmable Mix 1, set master to Flap, Slave to Flprn, select the switch that corresponds to your landing flap position (make it a 1) under position 1 make the down value increase to raise the ailerons when landing flap is selected.