Fire an event when Enter is pressed

Hello,
I'm using FCK as a rich text editor for a browser based IM software.
Since this is an IM, I don't want line breaks when the Enter key is pressed. Instead I want to call a function which will send the content of the editor to an XML file. How can I implement the call to a function within FCK? All the while disabling the '<br>' which is created when pressing enter and clearing the editor's content.

Any tips?