How to script an autoreply with specific signature


Back when I was using Entourage, I had a script that when triggered by a rule would reply and attach a specified signature. It worked great, allowing me to use simple HTML in my autoresponses instead of plain text. Can anybody help me translate this into Mail lingo? I've been struggling with it but I'm not that good. Here is script for Entourage:

tell application "Microsoft Entourage"
set theMsg to item 1 of (get current messages)
set autoMsg to reply to theMsg with opening window and html text without quote entire message
set signature type of autoMsg to other
set message signature of autoMsg to signature "Low Res HTML"
send autoMsg
end tell

Many thanks if you can help me out....