Using a Promotional Code to track Marketing efforts that lead to Membership Purchase

Whew. My Membership Manager gave me a doozy of a problem today. Basically, she wants to track how successful her marketing efforts are, which magazines, websites, etc. led to an online membership purchase. She wants to use a discount code to do this. No problem so far, right.

Well here's the trick. We don't want to offer an actual discount or term extension in order to do this. The incentive we want to use is a contest for anyone who enters a discount code to go on a back-scene tour of with our curator. But, there's no option for “Contest” in promotional type--there should be, hope the Altru Moderators are listening--and I can't list $0.00 as a discount or 0 months as a term extension. I even tried making the regular discount type work. It doesn't since it applies to admission, not membership.

So then we thought about adding a field to the Personal Information Screen, something like a “Enter Promotional Contest Code”. However, when I went to Manage Registration Forms, the field would only apply to admission, not membership. So even if I specified that only members could see the field, that still doesn't solve our problem since we want someone buying a membership not member tickets to see it.

I spoke with Support already and was told me to post here in case someone had a creative suggestion on what to do.