[rt-users] auto-populate email from short username?

[Philip Brown]

Well, lets try a simpler, hopefully easier to tackle subject line :)

lets say I have autocreate turned on. And accounts get created just fine 
when someone authenticates via web.  ... however, the autocreated 
account name will be just the username. no @my.com

What's the best way to get the email field set, with @my.com added, when 
the account is autocreated?