So I guess it is only ailerons that you have and your idea is to move them up for landing. Indeed, it is necessary to take a mixer to achieve the goal. You have to set the ailerons to "Ail+" (in German it is "Quer+"). This mixer offers basically what you need. For moving up the ailerons on both wings it is "SPOILER" what needs being adjusted. Of course for the brake you need to assign a controler in the setup unless you want to use flightphases - there you might do the setting in the control options and then use a switch to activate the brake.
So basically what I have tried to describe is the function "butterfl without flaps". Of course, in most cases an up-elevator-compensation is needed: you have to assign "elev+" (that is "Höhe+" in German) to the elevator servo. In the mixer option you can set the spoiler-value to about 10 % for a first try.