Had to figure this out for JC. You really need Nomads for this (can't do with Customizer AFAIK) and I can show you with that the 5 places / properties you need to set. Haven't tried it this way but if you DFDM any M4L file and pull up a record for a panel with a numeric field that already has the Calculator assigned, Fields 19,21,29,42,43 are what need to be set into your numeric UDF or for whichever field you're trying to effect.