Three zones configuration in Mikrotik 751 Router Os v5

HI!
I try to configure the 951g with 3 zones (2 WANs load balancing, LAN and DMZ), but I can find the way to do this.
951 appears as only 2 zones avaiable, with 2 WAN load balancing, but not DMZ.

Can anybody help me about it capabilities and some configuration example?

Thanks

G.