I dont think you can - The servers are continental by my knowledge - even though when you go online into the match rooms it gives you a list of servers to pick from - However if your in Europe - your in the European domain and so can only pick one of the European sub servers - such as UK-server or FR-server.
Thats not to say theres some way to by-pass this. Konami have loads of miscalaneous rooms at the bottom of the server list that my be trans-continental and allow for US v European games. Try inviting him via the PS network - that might get him into a server.
We tried everything to make it work earlier on today with no success. Tried inviting him, creating a lobby..it wouldn't find his username at all.
This is such a shame and a major flaw on Konami's part in my opinion. Since when did online play restrict what people you play and where they are located!? Last time i checked, online play involved the whole world...Street Fighter 4, Mario Kart, dare i say FIFA? "World" Wide Web means fucking nothing to Konami it appears. I dont give a shit about BLES numbers and different patches and all that shit. Overall its the SAME GAME no matter what way you look at it and should be playable in any country online with ANYONE on this earth! You would think in this day and age this problem would be non-existant. Not happy.