Using forms personalization: Disable batches.post checkbox on GLXJEPST when user views batch they cr

Greetings!

I am trying to "turn off" the post checkbox on the GLXJEPST form when a user views a batch they created.  I am able to disable the post button on this form (and GLXJEENT) in the when-new-record-instance trigger but can't figure out how to disable the post checkbox.  I tried using the when-new-item-instance trigger on batches.post by setting the enabled property to false if the user created the record.  When they clicked on the period column and then the post checkbox, it allowed them to check the box.  So close!  I added a propery to set the batches.post to N in when-validate-record and