Hello,
My recommendation would be to download and install BeeKit software tool, from
http://www.freescale.com/zigbee, It is a development environment that complements CodeWarrior IDE, where you can develop your application and generate xml file for CodeWarrior.
For your application, I would suggest to start from WirelessUART application example, included into SMAC codebase.
FYI, SMAC application development using BeeKit will not require the purchase of a specific license, beside IDE's one.
Regards