I've been looking at a similar issue on my spider and have come across this site here
that lists the various protocols and the pin outs of the plugs. The fact you got the 7 pin populated proberbly means you have the quote :-
"ISO and KWP Protocol Pins
If pins 5, 7, 16 and, optionally, 15 are populated, the vehicle supports ISO or KWP."
I bought the USB ISO OBD-II / VAGCOM / AlfaDiag KKL Interface from ecufix.com and loaded up the freeware virtual serial com port software and got the laptop to recognise the cable and load the drivers.
I also loaded the Alfadiag software but this is only for cars before 2001 so I've started looking at other options like the interfaces based around the ELM327 chip as this supports all the protocols.
I used this site here
and theres a tool chooser page and if you need more info on the type to use you can submit a query and they get back to you via e-mail.
Hope this adds some light and dosen't clouds the issue.
I've got a thread running on the Alfa Brera, GTV & Spider pages if you want too look