I would follow the same procedure as dghii described.
It is kind of a PIA to remove/reinstall the alternator but it took me only about 1/2hr to remove, I guess I was lucky. The MOST important step is to tap on the long bolt with a punch to push out the rear metal bushing. This is probably the most important step otherwise you can get stuck for hours. Follow the steps outlined here and you should be good:
Pelican Technical Article: Boxster Alternator Replacement - 986 / 987
I also found some YouTube tutorial videos that show you the different steps... what would we do without the internet
By the way, I did not remove the seat as a few of those posts suggested.
Let me know if you have any questions, I'll be happy to help. Good luck!!!