IPAC 2 - Retroarch config problem

[baviaannl]

Hi

I've recently built myself a bartop which went well although I'm struggling with the button configuration.  When I'm binding controls in the emulator within retroarch (NeoGeo in this case) I'll eventually have to map a B button, by doing so I loose the ability to go back on the menu's *as the default is B)  The newly assigned key doesn't perform that task.  I've racked my brain although I can't see how I can bind controls without using the B button.  I can't even see a way of changing the B button to something else.

Hope someone can help here, thanks in advance