Changing of save timestamp

Hi,

Our company would like to save the timestamp of the message to a Multi User Chat when the user hits SEND on the user's client.

I am thinking of using MUCEventListener's message received method, but how do I go about of changing the date openfire saves it to.  Also I am thinking of sending the unix timestamp the user has hit send will be sent using a custom stanza.

Any thoughts and suggestions to point me in the right direction?

Thanks.