Shoutbox

Hey, ive just started coding a plugin in vb but im not sure on one thing.
I want it so if my plugin gets a certain notifycode it will alter the incoming text in a certain way such as adding the time to the end of it and then place it in the chat window as normal.. a simple example:

if the notify code is "atest" then i want it to alter the incoming message so it has "test" at the front and the end.
From what ive seen the ReceiveNotify function's sText parameter allows me to get the text sent to me.. i can then say sumthing like mystring = "test " & sText & " test", but how do i get it to add mystring to the conversation window instead of the actual message they sent. Is this actually possible?

Thanks for any help

RooJ