Move Message(s) to All Mail

gistfile1.scpt

tell application "Mail"
	set theSelectedMessages to selection
	set theMailbox to "[Gmail]/All Mail"
	
	repeat with theMessage in theSelectedMessages
		set messageAccount to account of mailbox of theMessage
		tell application "Mail"
			move the theMessage to mailbox theMailbox of messageAccount
		end tell
	end repeat
end tell