I have contacted NetApp support and got the right answer. There was a network issue between both clusters. That was solved and we followed the next steps:
Resolution: Recommended to:
1.- Integrate VSC with SnapCenter which add that functionality.
2.- Add the SVMs to SC and be sure that the SVM names resolve the vserver mgmt ip address
3.- For the SV relationships to work correctly, destination cluster must be added to VSC and the destination SVM must be added to SC
Cause: Some VSC features need SnapCenter integration to work properly.
After this I got the snapmirror-label with the snapshots and the snapvault replications are working. No errors anymore and mount datastore from backup is working.
Marco