There's now a link exposed at spynet.com for reporting of false positives.
Posting in the .signatures group is appropriate for beta participants, but
there may be
circumstances where the direct report is quicker or easier to do, or a
vendor wishes to report their issue directly.
Here's the link:
http://www.spynet.com/falsepositive.aspx
Vendors who dispute a characterization of their software as "Potentially
Unwanted Software" and want to dispute that should continue to use the
Vendor Dispute Form:
http://www.spynet.com/vendors.aspx