FSX Autopilot Mach Reference

I want to set the autopilot mach reference value to the current mach number.
SimConnect_TransmitClientEvent with AP_MACH_VAR_SET seems to be the right function. But the SDK does not specify the units requested. Since the parameter to be transferred is declared as DWORD, it would not be usable to specify a mach number with at least one decimal fraction. I even tried AP_PANEL_MACH_HOLD_TOGGLE to set the current mach number. The only result in all cases is, that the throttle moves to idle as soon as I switch AP_MACH_ON. Does anybody know how to specify the mach number to be set with SimConnect in the autopilot system ?

By sending arbitrary values to AP_MACH_VAR_SET, and looking at the result of "AUTOPILOT MACH HOLD VAR" with the units of "Mach", I determined that it's expecting a scale of 100 integer values to 1 Mach.
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