Highlighting command parm in error in command validation program?

Folks:

For many years I've wanted to be able to highlight the field in error when
using a command validation program (like IBM does).

I've always thought it was related to the first 4 bytes of the message data
(that IBM says should be '0000') in the *diag message sent to report the
error, but no matter what value I put there it doesn't do what I want (I've
tried '0001', '0002', & 1 or 2 in binary).

IBM seems to send the relative field position, in binary, with messages
like CPD0071 (parameter xyz is required).

Is there a way to do this?

TIA

david