VM's loosing MAC address when mounted from replicated VMFS

Hi Everyone

Not sure if there is a quick answer to this.....

We run 2 Datacentres managed by one vCentre in the primary data centre.  We use EMC storage with Recover point doing the replication to secondary data centre. All running 5.5.

The other week we shut down some VM's, removed them from the inventory and unmounted the storage from primary data centre and mounted these in the backup data centre all through the same vCentre instance.  I re added the storage and when prompted I kept the existing VMFS signature, located the VMX files and added them back in the inventory through vCentre, and once prompted selected 'Moved VM' rather than 'Copied'.   What I noticed was the the MAC address's for the NIC's had changed

I done a similar test but add the VM's back to the inventory through the ESXi host directly and the MAC address was retained.

Any idea how to keep the MAC address's when managing the whole process through vCentre and why this is happening?

Thanks