[lime-users] setting one mesh device as gateway? (and nanostation M2 update)

Hi all, Thanks for previous help getting nanostation M2 working. It worked great downgrading first to AirOS 5.5.11 then installing the nano factory firmware. I have two M2's, and they have automatically meshed and we can connect two devices to their ethernet ports, the devices both get IP address and we can ping between the connected devices! All good! (Except there is no gateway IP issued - is that expected?) Now the quesiton is: how do we set one of the mesh devices to _take_ DHCP through the LAN port rather than give it, and to be the 'gateway' device on the mesh network, and then what will happen with devices that subsequently connect to the mesh? How will they get their gateway set? Thanks for help! Sorry if this is a bit of a newb question, it's not immediately clear from the configuration docs, any rtfm answer pointing to speciifc documentation also appreciated. James