not true - all 9700 hardware is identical - some functionality (eg 3g frequencies) is controlled in software/firmware by the vendor id/vsm (& until we get an updated mfi, we can't load a different vsm like we could older bb's) but uma hardware is there in all 9700's - thanks to the hard work of many others, I have tmo uma working on my att-branded 9700 & 9800 bb's - was just a matter of unlocking the engineering screens, downloading the tmo certs, & creating the proper uma profile.
this link seems to be closest to your particular situation (bell/rogers) - maybe it'll help:
ugh: I can't post links yet - go to howardforums & search for the thread titled
UMA WORKING!! Unlocked Bell 9700 -> Rogers Talkspot! OMG
(it's thread #1626452)