Gamepad input, axis OR button

Hi,

I have a game where I want players to be able to remap Gamepads and Keys for controlling things, however I have a problem with remapping gamepads.

Say I have a "Fire" command, mappable to a button, my problem is as follows.

The logical choice for an xbox controller is to press the Triggers, which are actually an axis. The logical choice for the DS3 is the trigger in the same place, which is however a button.

Is there any way to accept either/or? How would I handle this? At the moment I can only seem to solve this by having two different inputs, one for a button and one for an axis, which is confusing to an end user who wont even appreciate the difference.

Any suggestions welcome, thanks for your time.