You could try changing the event send by the external button to
1·(>H:AS530_CDI_Push,·Number)
Using the H: event will generate the same behavior as clicking the onscreen button. I have tested this RPN with AAO. There is a coorsponding AS430 event for the other unit.
I also tested
1·(>H:AS530_CLR_Push_Long,·Number)
assigned via AAO to the CLR button push with long duration.