Mirrorview/A between CX4-120 and VNX5200

We try to setup a mirrorview/a mirror between our old System CX4-120 and a new VNX 5200.

First of all we had some zoning issues, therefore we have only zoned CX4-120 B1(mirrorview port) to VNX 5200 B0 (mirrorview port)  and CX4-120 A1 (mirrorview port) to VNX 5200 A0 (mirrorview port). There is not other zoning between the two storage Systems.

The Management ports are in the same IP subnet.

From the unisphere Gui we weren´t able to enable the mirror Connection, at the end we managed to enable the Connection from naviseccli.

In the following we tried to generate a mirror from a MS Cluster lun (raidgroup on CX4-120) to a prepared lun on the VNX 5200 (pool), but we always get the error that the System cannot find the lun (even if we did that with naviseccli). We replicate only over FC

The VNX 5200 and the CX4-120 are in different Domains. We were not able to join it to the same Domain, but that is the same issue as with the older VNX storage Systems.

On the VNX System nearly every license is enabled, on the CX4-120 only MIrrorview/A is enabled (SAN Copy isn´t enabled)

Does anyone give us a hint what we did wrong about this replication Topic?