Hi, Ken.
The brake band adjustment can be found on the left side of the transmission case, underneath the firewall. The only way you can reach it is through the engine bay, but it's a really, really tight fit.
Remember to adjust the band in small increments. This is frustrating to do, what with the adjuster's location, but you don't want to damage anything.
There's a cutaway diagram of the transmission in my locker at:
http://www.subaru-svx.net/photos/fil...ckets/6279.jpg
The brake band adjuster can be seen poking out of the top of the tranny, just behind the line I added to show where the differential and gearbox meet.