Hi,
I do not give you a hint for the RAppID setting.
But generally, the pad itself should be programmed to eMIOS function by PCR[PA] field in case of output and IBE bit for the input.
The eMIOS GPIO input /output mode is set by programming the MODE field of CCR register.
For GPIO input mode, the input pin status can be determined by reading the UCIN bit.
For GPIO output mode, the unified channel is used as a single output port pin and the value of the EDPOL bit is permanently transferred to the output flip-flop.
BR,
Petr