Static IP address for LB2120

Hello,

I purchased a LB2120 to use as a failover for my internet connection.  I have the sim card in, and am able to get internet connection via cell phone service.

I plugged in my cable modem into the WAN port for the primary internet service, and for it to fail over to the cell service.

Problem is that there is no where in the settings to set a static ip for the WAN port connection.  Is there a way to set a static IP?

Thanks,

Zhiyu