Wrong IP Address being presented via RED connection

Hi,

We have a network connection into a main site via a RED, this is all working fine. On this site we standard VLAN and a VOIP VLAN and ths is configured and we are able to ping all devices and everything is working. The Phone system is in a Datacenter and the setup is as such.

XG's LAN IP's

Default VLAN      192.22.48.8

VOIP VLAN          192.24.48.8

Phone in DC ---->  Private WAN ---->  Main LAN ---->  RED Remote LAN

192.22.241.0                                        192.22.48.0       192.22.19.0

                                                              192.24.48.0       192.24.19.0

All is working apart from the IP address being display in the phone system as IP of the connected device is the XG's Main LAN address and not the actual IP of the phone at the remote site.  i.e.

The phones actual IP is 192.24.19.100 but on the phone system it is being reported as  192.22.48.8

Is this just the way it is or are we missing something here. Thought the XG would act as a router in this setup but appears to be doing NAT.

Thanks

Andy