Need to add Trusted Site when file format and extension don't matc

[tlw7958]

I need to add a trusted publisher but am not getting a macro warning as
described here: http://office.microsoft.com/en-us/help/HA100341381033.aspx.
My problem is that spreadsheets generated in asp/aspx and given the xls
extension are not recognized as xls files and a warning is given
(http://support.microsoft.com/kb/948615). I want to get rid of that warning
for files coming from a trusted website, but not for all files. Is there a
method for doing this?

Thanks,
Tammy Westmoreland
(e-mail address removed)