Collecting Air Supply Autographs

[HitchcockFan]

Greetings!
I am a fan of the band Air Supply, a soft rock duo that has been releasing albums since 1976. The duo is made up of Graham Russell and Russell Hitchcock.
I would cherish the autographs of these two men, but I have a few questions.
First, does anyone know if these men even sign autographs through the mail? I am planning on writing Via Venue if possible. Their 2009 Word Tour has many concerts planned in the US, so my first bet is to try them through an event.
I want to make sure, however, that these men aren't the kind that never sign autographs, even for fans at the concerts.
Hopefully a more experienced collector in this field can offer some insight and helpful direction.
Thanks!

For more information about Air Supply:
http://en.wikipedia.org/wiki/Air_Supply
http://www.airsupply-online.com/