Hope I'm not repeating here but have just fitted my Autocom to my new 2008GS and have a couple of observations that may help.
On my previous two GS's the Autocom unit had to be attached to the handbook bracket at the rear of the seat which was far from ideal. On the new bike the tool tray is slightly bigger and deeper and makes an ideal place for the unit to sit. As there are now no fuses under the tool tray there is plenty of room to fit the GPS block and a Bluetooth adaptor. The whole process was much easier.
Also having considered it for a while I have now fitted my Kenwood in the topbox. I drilled a hole, cut the radio extension lead, passed it through the hole, soldered the wires, covered each one in a tiny heat shrink wrap and then covered all six in a large shrink wrap. Maplin sell a cheap cable exit gland with a sleeve that makes sure the exit hole is waterproof. So far seems to work perfectly.
On my previous two GS's the Autocom unit had to be attached to the handbook bracket at the rear of the seat which was far from ideal. On the new bike the tool tray is slightly bigger and deeper and makes an ideal place for the unit to sit. As there are now no fuses under the tool tray there is plenty of room to fit the GPS block and a Bluetooth adaptor. The whole process was much easier.
Also having considered it for a while I have now fitted my Kenwood in the topbox. I drilled a hole, cut the radio extension lead, passed it through the hole, soldered the wires, covered each one in a tiny heat shrink wrap and then covered all six in a large shrink wrap. Maplin sell a cheap cable exit gland with a sleeve that makes sure the exit hole is waterproof. So far seems to work perfectly.

