I don't think this will work, deCONZ (the software) is designed to be coordinator software, not a general purpose mapping utility. deCONZ will map its own network if it's set up as a coordinator.
The conbee II can be used as a router (but not really sure why you'd want to) or a zigbee sniffer using ZShark which is their addon for Wireshark. I don't believe I've ever seen it used as something that can map a zigbee network in isolation though.
You'd probably be better off using an XCTU with an Xbee - Everything Xbee
