Access 2000 SendObject to Excel

I’m using MS Access 2000

I’m using the following command:
“DoCmd.SendObject acSendQuery, sQDName, acFormatXLS, sEmailAddr”
to create an Excel spreadsheet and e-mail it to a specified address.

My question is this:
How can I have a formula ina certain cell?

My query is pulling Gross Weight and Tare Weight from a database and including those as 2 columns in the spreadsheet. I want a third column to be the Net Weight (gross – tare). I need to use a formula because once the user receives the spreadsheet via e-mail, they have the option of modifying the gross and/or tare weights. Thus, I would
like the “Net Weight” to recalculate as the user changes the gross and/or tare weight columns.

Thanks in advance,
Mike T.