Getting message list to show up in contacts?

[amca01]

I'm having a problem with a message list I've created. I can choose it from the contacts list, and send a message to it. But if I want to forward a message to that list, I can't. If I choose that message, then Forward, and then click the "To" button beside the address field, the "Show Contacts" window pops up. But the message list is now nowhere to be found.

How can I get the message list to appear under "Show Contacts"?

Thanks,
Alasdair