If the Violet/White and Orange/White SWC wires are present on B36, you'll need to tap them (at any convenient location between B36 and the steering column). Splice in new wires that can reach from there to i26.
At i26, you'll want two new wires with pins that will fit. You can get those from another car being parted out (any ~1995-2007 Subaru's radio harness and the power harness for a McIntosh amp use the same pins).
You can also get them from an aftermarket "reverse" radio harness (such as Metra 71-8901). That is the type you would use to install a factory radio into a different car (or to repair a damaged factory radio harness).
If the SWC wires are not present at B36, I'm afraid you will have to add them to harness B68 at the steering column. That is the same type of mod that we must do on North American 2005-2007 models when adding SWC buttons to a car where they weren't factory-installed.

