Well, the IamLegend has the HD logo beside the 501 channel
The others do not have any HD 'stamp' so I assume it's Standard
Now when I clicked on IAL it did say that it's available in 1080P and the test blah blah
but the only one that I am sure is HD is that one
I took this from my non HD slingbox so it's not in widescreen but
mine is a 722... wonder if that has anything to do with it...
your receiver has to actually download one of the movies before 501 will show up. Give it time since it does send to you when it has the available space (aka not in real time).