They can be read with the FMPGet command (1.5.3) and written with the FMPSet command (1.5.10) using the FMPI_xxx index.
Some settings are read only and are marked as r, others can be written and are marked r/w.
When it is r/s it means that you can write the value only if it is not yet determined. To be used carefully.
The FMPGet and FMPSet commands always use 32 bits values.
When a value is less than 32 bits long, the unused bits are zero.