For me it worked. Logged into the Backer portal with my forum name and password and then backed via Paypal (thanks for the possibility!).
The Devs said on fig that they will doing updates on Fig and on the Backer Portal Emails on how the Paypal progression goes and if new stretch goals are hit.
Again thank you Obisidian for making POE1 and a very good campaign on Fig. I await Deadfire! ...and have to buy a better graphic device, when I see footage of the actual game. ;-)