Source code, setting up explanations, and everything moved to: https://github.com/rromanotero/xbee_mac_interface .
(Updated Nov 15, 2014). The idea is simple. Xbee 802.15.4 radios cannot communicate off-the-shelf with TinyOS-based moted. They are supposed to, but they do not. Sometimes communication is not possible because of parameter mismatch. In particular, a) TinyOS is set in low power listening mode (not supported in Xbees); or b) Xbees are set up [...]
This interface allows an application to tell the Serial Dispatcher, which is in charge of packet formatting, whether to use headers or not in the serial packets.