I don't think I was specific enough in my post, I meant when trying Ad-Hoc multiplayer mode. I can get into the lobby, and go to rooms, but if I want to do missions, it just hangs when loading the first block. (Unless that's what you were talking about lol)
A friend and I tried to netplay PSP2 a couple of times using Hamachi and Evolve, but we got almost the same result with both; being what you've experienced. In addition, we were able to do battles.
Open missions were a no-go. I haven't tested anything else.