I never knew that Paypal FF is irreversible. I am sorry for your lose. You should not send FF first neither the scammer too. When a user do not have much rep here, it's always advisable to use escrow.
Archive:
http://archive.is/xnrWNI will tag the guy and I hope he leaves this kind of scamming profession.
Edit:
Tagged
I know that`s my fault to start trade with a guy with no trust.. I did just because I`m in the same position..