Hi Rampage, thanks for your answer. Sorry about that. I bought the kit there. The website doesn't seem to have an english version. Anyways, it's a pretty generic keyless entry system and while I can't find the installation notice online, the cabling is very similar to the picture above, i.e. The white and white/black are the positive and negative triggers while the yellow and yellow/black carry the + 12V and the orange and orange/black the GND.
I don't care about triggering the lights so I ignored the other cables. I just plugged the +12V (red) to the yellow/green cable of the B-52 connector above the fuse box in the driver's side kick panel, as explained in the subaru installation instruction and the GND to the nut holding the door lock timer metal frame. That works, my keyless entry box turns on and is triggered by the remote, I hear the relays clicking.
So what is the trigger on these old subaru? How would you connect the cabling?