All you really need to do is get the plastic piece that the leather around the shifter goes into up and out of the way so you can see down into the shifter area. It is the part that the letters PRNDS(L) are attached to. The plastic is held down with clips on each corner, so you can just kind of pull it up and release each clip.
Once you've done that, there should be 3 wires coming down from the knob going into a connector. These wires are what connect to the +/- buttons. One of the three is a common that the other two make contact with when a button is pressed. You could wire into these three wires with any (momentary) switch you want and put them anywhere you want.
I have looked into this, but I have the non-SelectShift version with the hill assist button on the shifter. On my car, there are two wires coming down from the knob for that button.
2012 Ford Focus
Sonic Blue SE 5Dr
203A Package, 6 Speed Auto
Mods: Debadged, 30% LLumar CTX Tint, MS3 RMM, Steeda RSB