Chronos firmware uses "sx" and "mx" for a submenu functions. "sx" and "mx" functions are specific for each different screen or display you are in.
"sx" function is accessed via pressing "UP" button - it scrolls through available subfunctions (for example, in acceleration mode Y -> X -> Z)
"mx" function is accessed via pressing and holding "*(star)" button for ~3 seconds - it allows to adjust temp offsets, set date and time.
Not all displays has "sx" and "mx" enabled or programmed, you have to look at the firmware and change it to suit your needs.
I suggest to read documentation of eZ430 Chronos (pdf file) and look through provided code.