I've moved this question from http://www.howtoforge.com/forums/showpost.php?p=303835&postcount=5 to here since I need to do this over this weekend. Falko/Till: do you see any problem with installing the Wheezy version of courier-maildrop onto Squeeze per http://www.arty.lv/ispconfig-3-0-4-6-autoresponder-on-debian-6-squeeze/ ? This is due to autoresponder placing text below original message and -N switches not working. Thanx.
If anybody needs to know, this worked and autoresponders now perform correctly with -N switch from previous thread.