Sony Ericsson :: Flashing / Debranding My C905a?

I am trying to debrand my SE phone, using this article as a guide: http://www.associatedcontent.[....]nd_a_sonyericsson.html?cat=15. I installed all the necessary programs and drivers, created an .xml file (for generic American version), transferred it to phone, tried SE Update Service, no go. Says I already have the newest software. I tried creating a new .xml file, but this time using Western Europe instead of America. Still, Update Service says my software is new enough. Then I tried going back and creating a generic American .xml and using Update Service to reinstall my OS, but that only reinstalled the old and customized AT&T OS which is what I'm trying to get rid of. So my questions are: 1) I was sort of reluctant to debrand in the first place, but what is the worst thing that can happen if debranding fails? 2) Is there some other CDA number I can use (instead of America/W. Europe) and still be able to use my phone with my service provider? Perhaps Central or Eastern Europe?