JC, resurrecting your old post here, but having the same issues while I'm international. Have you have any luck with the option to switch back to automatic if the network is not found? That doesn't ever seem to work for me.
When on Wifi in the hotel or office here in Manila, I turn off EDGE to make sure I stay on Wifi and make calls for free.
When I roaming the city, I turned the EDGE back on. It goes to one of 2 providers, Smart or Globe. If on Globe, I never get any email, but with Smart I do. So I turn the phone to Manual and select Smart. That works fine, but if I go back to Wifi, UMA never connects.