How can I see the files and directories on the Xbee / Zbee Gateway ?

i would advice not to. If you want to send large amounts of data such as directories from PC’s, I would suggest using WIFI or Ethernet. Serial communications is inherently slow and a Mesh protocol such as Zigbee or Digi Mesh is even slower. Not to mention, that you would need to have software that could first break up the packets into 84 byte chunks and then reassemble it.

Thanks for response.

OK, However I only want to view the directory and what files they contain. How do I do That ?

You need to use something like a VPN connection or to share a Map a directory. All of which require more bandwidth than what any Mesh network can provide.