Mail Script - Reply from different mailadresses .

Hello. I have a script that I use to automatically respond to emails. The problem is that I have multiple accounts in Applemail and I want the script to send replies from the account that received the letter. How do I do that?
This is my code

tell application “Mail”
set theSelection to selection
repeat with thisMessage in theSelection
set ReplyAddress to reply to of thisMessage
set theOutgoingMessage to reply thisMessage with opening window
repeat until name of front window is (subject of theOutgoingMessage)
delay 0.3
end repeat

	set content of theOutgoingMessage to (myReply) as rich text
	set A to to recipient 1 of theOutgoingMessage
	set address of to recipient 1 of theOutgoingMessage to ReplyAddress
	set subject of theOutgoingMessage to "unsubscribe avanmäl"
	send theOutgoingMessage
end repeat

end tell