EpiUltraGrid ExtendedProperties formating a decimal as an integer

The the Sales Order Entry Summary, we show the OrderDtl Available and Onhand fields. These fields are decimal, but for us always contain a integer value. To save space on the screen, I want to display as a integer. I changed the ExtendedProperties("Format") = "nnn,nnn." This worked until we came up with a negative available which displayed an error message. So I tried "-nnn,nnn." no luck. I tried "###,##0" and ">>>,>>0", but 2 decimal places display.

Has does anyone have a similar EpiUltraGrid where they have formated a decimal as an integer that allows negatives?