We found the solution!!
The DMX 3 storage gets confused when presenting the R1 and R2 at the same time to an ESX server.. it's actually the logical volume manager wich causing the problem.
The funny thing is that DMX 2000 does not get confused.. So now we are aware of this behaviour Disaster Recovery works fine.. without Diskresignaturing and without renaming your datastore or update your .vmx files.. just do a failover , reregister your VM's on the new ESX host in Virtual Center and power on the VM's