Even if you don't use Google Apps it's also not possible to have own XMPP address that happens to look the same as an e-mail address that Google knows about (even if it's non-Google address and non-Google XMPP). When they see it they route GTalk users' messages straight to GMail chat, bypassing XMPP.
> Even if you don't use Google Apps it's also not possible to have own XMPP address that happens to look the same as an e-mail address that Google knows about (even if it's non-Google address and non-Google XMPP). When they see it they route GTalk users' messages straight to GMail chat, bypassing XMPP.