Is there a hack for this?

[Djburn]

No hack is needed, when you send a PM to someone you can select any of these options below the message part before you send the message

Request a read receipt for this message
Save a copy of this message in your Sent Items folder.
Show your signature
Automatically parse links in text
Disable smilies in text

if you select request a read receipt for the message you will get a notice that the message has been read

i hope this helps