Making Commodore 64 and Amiga emulation usable

[MattMorphett]

Has anybody figured out how to make C64 and Amiga emulations usable on Arpicade?
I'm about to put some research into it so I figured I'd ask here in case anybody has solved it. Once I get to the bottom of it I'll post my finings here.

The problem...
Basically you often need to access a virtual keyboard (with a joystick guided mouse pointer) and the emulator's settings menu to do things like swap disks or move control to different joystick ports etc. On the GCW Zero and other emulation platforms you simply map a couple of your control buttons (or a combination of button presses) to those functions and it all works pretty well, if a little clunkily.

I believe Arpicade runs Retroarch to achieve emulation of these two platforms and the defaults for instantiating these functions is not obvious. You can raise they keyboard on the C64 (vice) by pressing the "a" button on an attached keyboard but it isn't mapped to anything sensible through the JAMMA harness - i.e. no obvious buttons. Having achieved that, you can't actually move the virtual pointer to press buttons, there's another keyboard bind for that.
The Amiga keyboard appears is you press player 2 start. etc.
It's inconsistent and not very usable.
The ideal would be that you press a button or button combo (e.g. maybe P1 start and P1 Right) to get the keyboard or the settings menu.
...but it isn't obvious how to set that up in the Retroarch menu (which you can raise with F1 on your keyboard).

Anyway, I just wondered if anyone has found a clear, or at least easy-to-follow approach to sorting it out?