Copying entire Mail message content into Excel using Applescript

I am using the code below to try and automate the copying of entire emails from my Mail app to an excel document. The code works fine, but all of the email messages are truncated to a limit of 256 characters. I presume it has something to do with the line " my SetMessage(content of aMessage, theRow, theSheet)". Does anyone know how to fix this so that the entire email message is copied over?

tell application "Microsoft Excel"

set LinkRemoval to makenewworkbook

set theSheet to active sheet of LinkRemoval

set formula of range "D1" of theSheet to "Message"

set formula of range "C1" of theSheet to "Subject"

set formula of range "B1" of theSheet to "From"

set formula of range "A1" of theSheet to "Date"

end tell

tell application "Mail"

set theRow to 2

set theAccount to "Google"

get accounttheAccount

set theMessages to messages of inbox

repeat with aMessage in theMessages

my SetDate(date received of aMessage, theRow, theSheet)

my SetFrom(sender of aMessage, theRow, theSheet)

my SetSubject(subject of aMessage, theRow, theSheet)

my SetMessage(content of aMessage, theRow, theSheet)

set theRow to theRow + 1

end repeat

end tell

on SetDate(theDate, theRow, theSheet)

tell application "Microsoft Excel"

set theRange to "A" & theRow

set formula of rangetheRange of theSheet to theDate

end tell

end SetDate

on SetFrom(theSender, theRow, theSheet)

tell application "Microsoft Excel"

set theRange to "B" & theRow

set formula of rangetheRange of theSheet to theSender

end tell

end SetFrom

on SetSubject(theSubject, theRow, theSheet)

tell application "Microsoft Excel"

set theRange to "C" & theRow

set formula of rangetheRange of theSheet to theSubject

end tell

end SetSubject

on SetMessage(theMessage, theRow, theSheet)

tell application "Microsoft Excel"

set theRange to "D" & theRow

set formula of rangetheRange of theSheet to theMessage

end tell

end SetMessage