Some do open with the hinge on the front ~ ours does. I think you answered your own question...the awning support. When we add an awning to ours, we have to make a decision:
1) ZipDee = only open door 90-degrees
2) Tent Pole style = open door 180-degrees.
I recently found a third option...
if I can find an obsolete ZipDee awning cleat, then the awning arm can be detached and placed vertically so the door can open 180-degrees. Let the search begin!
Shari