Verifying digital signatures of executables

I have a web service that allows clients to download updated versions of
setup executables from the web server machine. It's pretty basic you give the
webservice a product name and a version and if there is a newer version of
the product it pushes it out with BITS.

All of the setup kits we push out are signed with authenticode. What I would
like to do is have the web service verify the digital signature of the setup
kits before they are pushed out. What is the best way of doing this in ASP?

It seems that there is a winapi function called WinVerifyTrust() that can be
used to do this but is this the most appropriate solution for a web service?