insert line returns in text for email shell script

Hi,
I have a shell script that sends emails but I would like to format the message by inserting line returns in the message body. I have added the return command into the message body that I know would format correctly if I was to display a dialog but I can’t seem to keep this formatting when I run the shell script.
Thanks,
Nik

set theattachmenrt to POSIX path of success_lowres_pdf
	tell application "Finder" to set attachment_name to name of success_lowres_pdf
	set msgBody to "File: " & DocName & return & "of folder: " & master_folder & return & "Has passed Stage 1 PreFlight checks." & return & "A proof has been printed to the Dixons Fiery. If you have any further questions regarding the file please contact a member of the Pre Press department."
	set msgSubj to "Stage 1 PreFlight Success for " & DocName
	set mailDest to email_address
	do shell script "(echo '" & msgBody & "'; uuencode  " & "'" & theattachmenrt & "'" & " " & "'" & attachment_name & "'" & ") | mail -s '" & msgSubj & "' " & mailDest

This works for me so I don’t think it’s the returns… it must be something else.

set messTo to "someone@somewhere.net"
set messFrom to "someone@somewhere.net"
set messSub to "Message subject"
set messBody to "line 1" & return & "line 2 " & return & return & "line 3"

do shell script "echo " & (quoted form of "" & messBody) & " | mail -s " & (quoted form of messSub) & " " & messTo & " -f " & messFrom

OK, I got an attachment working too:

set messTo to "somebody@somewhere.net"
set messFrom to "somebody@somewhere.net"
set messSub to "Message subject"
set messBody to "line 1" & return & "line 2 " & return & return & "line 3"

set attachmentFile to choose file
set theAttachment to POSIX path of attachmentFile
tell application "Finder" to set attachmentName to name of attachmentFile

do shell script "(echo " & quoted form of messBody & "; uuencode  " & quoted form of theAttachment & space & quoted form of attachmentName & ") | mail -s " & (quoted form of messSub) & space & messTo & " -f " & messFrom