Webform front end to RT, how to get email address? -- SOLVED

The easy way to do this is to have your app spoof the sender of the mail so
that it appears to come from luser@foo.com instead of your app. That’s how
we do it.

Thanks. We had someone else write (and host, grr) the front end, but
after some convincing, we managed to get their devs to spoof the
envelope sender.

Thanks Gene and Todd for your help with this.