Do the following to have the ReplyToAuthor script activated:
1: while in eudora, press insert+0 to bring up the script manager
2: now press ctrl+l to bring up a list of scripts
3: press the letter r till you hear ReplyToAuthor and press enter
4: press ctrl+d then tab to the assign to hotkey and press ctrl+shift+a
5: tab to the o.k button and press enter.
6: press ctrl+s then alt+f4 to exit the script manager, you're done.
Now when you wish to reply to author, simply press ctrl+shift+a and you will be placed on the first character of the quoted message, you can simply start typing there. Remember to press enter twice when you are done typing your message to place a blank line between your text and the quoted text.