FINALLY! This is a life saver of a post. I just fully upgraded to the OFFICIAL Wind Hellas 5.0.0.509 OS, and i'm with Rogers Wireless......HOWEVER..
Just FYI for people running Windows 7, make sure you check everywhere in the c:\users\USERNAME\appdata.....for the Vendor.xml file. There's another "common files" folder there somewhere and in that is the extra Vendor.xml file. Also make sure to view all hidden files, because its hidden. I tried to do a search but i didn't get any search result for "Vendor" no idea why...so just make sure you manually look and delete.
Once i finally deleted both Vendor files my BB Desktop Manager recognized the new OS 5.0..., however once i clicked next...it said no update necessary...this is why you just bypass the DM all together and just use the "Loader" app. It does work beautifully.
I had a successful install of this newest OS, and there are no flaws at all, everything works!
even facebook lol another good point of this OS is that it automatically updates your programs on initial startup
This Curve 8900 is running wayyyy better than on the 4.6 OS