@hoeveler If core input remapping doesn't work, you can either do a configuration override (per-game) or manually add the input configuration in a game dependent configuration file (explained also on the same page).

@mitu - I was able to use mame4all which sees that roller correctly - very confusing how the retroarch cfg works..
Example:
To see the spinner for arkanoid I had to switch to mame4all and looking at the input shows J1 RetroPad -X and +X for the controls... I don't know how to map that here as the spinner doesn't provide anything like that in the mame config (tab) and when I edit the .cfg file I tried adding the following:
input_player1_left_axis = "-0"
input_player1_right_axis ="+0"

with no luck... still unable to get the spinner working - howbeit the trackball works out of the box with mame4all.... lol

Somebody needs to write up a config walkthrough for retroarch and that joystick system... greatly.