Move Filter and SET to first item?

Hello,
I’m trying to move a category (RULE_DATE) to the filter tray and then set it to the first item. It doesn’t always set it to the first item. In the model attached, it currently goes to 12/05/2015.

In the script, I’ve defined a string to grab a date from the menu (12/03/2015) but don’t know how to set the RULE_DATE category to that value once it’s moved to the filter location.

Thank you in advance,
Andy