Remapping saturn controller for c and z buttons

Hello! Trying to remap a retro 6 button sega saturn controller for the beetle emulator. No options I can find to remap for the c and z buttons. I tried in game controls menu. The setting input port one menu. I see alot of people suggest turning the controller option to md 6 button pad. But it never gives me that option. Just either retro pad or retro pad with analog. Or in emulation it gives control pad. 3d pad. Then all the weird specialty saturn controllers like the gun. Would love to get this figured out. The games seem to run fine. But most the games I want to play use the 6 button pad.