firmware download for RCM4500?

Hello,

I have a zigbee rabbit (RCM4500) working as a gateway, hooked to a telit cell modem running GPRS and connecting to serial port C. My client is interested in downloading firmware updates to this rabbit but when I looked at the
Download Manager sample it says it doesn’t work for the 4000 processor.

Can anyone point me in right direction for accomplishing this function?