connect zigbee sensor to gateway

Hi

I have a digi xbee industrial gateway, and I’m trying to connect “spirit zigbee radiator thermostat”
But I can’t seem to find any information on how to connect a non Xbee device to the gateway.
Maybe I’m overlooking the right information, but any help would be usefull.

Thanks in advance
Floris

https://www.digi.com/support/knowledge-base/zigbee-home-automation