There are a few posts on this:
http://forum.mikrotik.com/t/rb-912uag-5hpnd-and-mc7710/78254/1
http://forum.mikrotik.com/t/wireless-integration-problems-proxim-mt/6051/1
http://forum.mikrotik.com/t/wireless-integration-problems-proxim-mt/6051/1
http://forum.mikrotik.com/t/working-with-mc7710/80733/1
I think you just add your details to the LTE interface, then add a DCHP client to the LTE interface.
Sorry I can’t be much help. I don’t have one to test with but it may help a bit until somebody with one can chime in.