I realize this post is very old, but to implement CCX on WinXP you need to replace the WinXP WZC supplicant with a third party supplicant, using an IM driver. You also need to create a new GUI for network configuration.
For example, Intel and Cisco Windows WLAN adapters (which support CCX) require you to uncheck "Use Windows to configure my wireless network settings", then use their own client application to configure extended features such as CCKM.
Dennis
dB Performance Inc.