My game is "Battlefield 2: Complete Collection", which combines all the games on to a single disk. So, technically, it should work.

Also, in small print, it says:

Registration via internet required for Euro Force and Armored Fury content. Registration required to access online features of Battlefield 2 and Special Forces Expansion Pack.
That's fair enough - I have three seperate serial numbers for the game: one for BF2, one for SF, and one for the mini-expansions. However, after registering Special Forces through EA Link (or whatever they changed the name to), I still can't access the SF maps.