write a Scratch extension to send data to serial port

Hi there, I need an extension for Scratch (MIT Media Lab) that allows you to write to the serial port. Basically I want to send some data to a XBee module, which is hooked up to a COM port. In Scratch, I need a new block that accepts a variable as an input and sends this to a com port (which obviously needs to be configurable with baud speed) etc as well. I believe this is an example of an extension: [login to view URL] to bid, you obviously need to download Scratch (free) and ideally have XBee modules as well to test, but a serial monitor should do, too. Thanks, Marc PS: I would expect this to be on the lower end of the project price range for someone who knows what they're doing ;-)