NAT problem

My network structure is as follows:

internal: 192.168.0.0/24 gw: 254(astaro)
External: 211.174.X.1(astaro) gw: 254
External second: 211.174.X.2(astaro)

internal - ASTARO -External

Unusual NAT problem

DNAT: Internet -> 211.174.X.2 convert 192.168.0.2

The problem
SNAT problem: 192.168.0.2 -> 211.174.X.2 convert 211.174.X.1

can't convert to 211.174.X.1

A solution to this problem?