said by resolutionFi :
This is so stupid that they didn't have a "native" output option to their STB.
But thanks for the comments I will stick to 720p.
I'm guessing the reason for this is it would take long to change channel if you were switching between 720p and 1080i and 480i channels.
Follow up question Is it 720p for Bell ExpressVU as well? In which case, does setting it to 1080i lower the quality because of conversion?