I am about to install a Passport 8500 in our E320 in the same way. I was planning to pick up my volt meter and a small pin and try them one at a time during the holiday. I'll let you know when I find out.
Of course, if someone finds out first, please post.
BTW, I found this chart at CustomCarSound's website (http://www.CustomCarSound.com/):
P o w e r
Memory (+12v Constant) Red
Ignition (+12v Switched) Black/Yellow
Ground (-) Brown
Power Antenna Blue
I'll probably use it as a guide.
[This message has been edited by bertrandchiu (edited 11-21-2000).]