Well, maybe I've found an answer to my question...

I noticed that I can send a request for this page:
http://127.0.0.1:10000/postmessage?radiobutton=sender&checkbox_WB_X=Whiteboard&messagetype=typehere&messagecontent=contenthere&post=postand the effect will be to send a message to the whiteboard, exactly as if it was sent from an external module...
In this way I can make another application to interact with the whiteboard only through http requests (and only for posting "simple" content, of course).
Maurizio