Admin Forum:Enhancing Welcome-message-user

I would like to "improve" Welcome-message-user on a number of wikis to echo the custom signature of the welcoming admin rather than the default Username (talkpage); that's the $3 parameter. The help page does say whether it can or can't be done. I don't want to experiment because if I get it wrong, the first new editor would get garbage as a welcome. Thanks.-- 16:13, October 7, 2012 (UTC)