NAT-ing Issue - URGENT

Dears,

i would appreciate your help in the below case as i couldnt find a solution yet.

Trust - 192.168.1.1

Untrust - x.x.x.34

            - x.x.x.35

i want to do NAT for the private IP address with the two public IP addresses, my issue here is whenever the traffic is going from 192.168.1.1 to the internet, it takes x.x.x.35 as its public IP, while i need to enforce it to have x.x.x.35 when going outside the network.

i have configured two MIP entries for this and its working, i only need to inforce it to go using x.x.x.34

thanks in advance