Styled text in email

I have a script that generates an email having a fixed format :

set txt to "Open Bugs:"
# Not the actual code :)
repeat with theIncrementValue from 1 to 3
	set theBug to "Bug" & theIncrementValue
	set txt to txt & "
" & theBug
end repeat

tell application "Mail"

set newMessage to make new outgoing message with properties {subject:"Test", content:txt & return & return}
tell newMessage
set visible to true
set sender to ""
make new to recipient at end of to recipients with properties {address:""}
end tell
end tell

This generates email in the following format:

I would like to make the title “Open Bugs” bold. So the email body should look like this when the compose window comes to the foreground:

How can I make the just the title bold using AppleScriptObjC ? Is there a way I can mimic

in AppleScriptObjC ?

Try making the first line after “tell newMessage” :

set font of characters 1 thru 10 to “Arial Bold”

or whatever bold font you want.