How to add QSERHA in Sage 50

I need to add a reimbursement type for QSERHA that will keep it from being included as part of Gross pay. But I also will need it to report in box 12 as a FF on w2s as well. I cannot find anything showing me how to add a formula in the User Maintained tax formulas for this. Can anyone tell me what I would enter in the formula field to just tell it not to be included as part of GROSS?

Thank you