Is it possible to explicitly set the Return-Path on an outbound mail
message using CDONTS and ASP? I want mail bounces to be sent to a
particular address, but ASP/CDONTS appears to set the Return-Path to
match the From address, which I don't want.

It appears that Return-Path is not a regular mailheader, but actually
holds the value passed in the MAIL FROM smtp command. I've run into
some discussion of this on the web, but everyone seems to be having
the same problems I am (can't get it working right).

The only solution I've found so far is to use the "masquerade domain"
in the IIS SMTP server properties -- and then I would need to set up
an MX and mail handling for the masquerading domain to catch mails
delivered there.  Obviously not the optimal solution.

The acceptable answer will tell me if this is possible to do without
using domain masquerading, and if so, please include a working code
fragment that accomplishes this.  If this is not possible, any
suggestions of better (and free) alternatives to the domain
masquerading workaround would be appreciated.