Having trouble with binding certain buttons... (Logitech F510)

Hey I'm using a Logitech F510 controller, and it seems to work fine with the standard xbox inputmap, with the GUID and name changed to fit... BUT:

I can't bind anything to the left DPad button. Maybe I'm doing it wrong, I'm using "dpadl", is that wrong?
The top left back button "btn_l", also doesn't work. The right one "btn_r" does :/

Any ideas?

Edit: For reference, the F510 is supposedly, exactly the same as the F710, except wired.

Edit 2: Okay so the left dpad button is, apparently, bound using "lpov". Um... What? Why? I'm so confused... Oh well, one problem out of the way! Still can't use my left back button

Edit 3: Okay so the back button can be bound now. I'm not sure what I did wrong. Meh I guess this is solved then. I don't get why the left dpad button is "lpov", but whatever I guess. It works