Aha thanks.
I probably did find a way to do so:
1) get the account (you want to copy games from) registered as account belonging to the PSP Go.
2) do the same with the (old) account you want to copy the games to
3) When logging in to the (old) account, you get to see the option: My Account where you can import and "old" account, since the PSP Network found you registered a "new" account as PSP Go account.
I'm going to try it tonight.