Gh5 Shutter and F control button options

I have a nauticam housing so theres only 1 dedicated button to switch either the f stop or shutter speed,  since the housing doesnt have a the front wheel option on the housing. I have my back wheel button for f stop so does anybody know how to set a custom button or be able to quickly adjust shutter speed without going into the menu and switching the settings manually each time?

The housing has two wheels one for front and one for back it controls everything on the camera no buttons are unmapped except some function ones?

I figured it out theres a wheel near the trigger button. Thank you