It's not mappable by default, for now, but expect that will change in the future. (Hope so anyway).
In the interim, you can manually edit the default.lua in x:\installpath\Eagle Dynamics\DCS World\Mods\aircrafts\F-86\Input\F-86F\joystick and add in the missing commands if you like.
Here's the thread where you can find the missing commands for most of the aircraft. http://forums.eagle.ru/showthread.php?t=125245