Well - although I can now select a MetroCluster in the workflow dialog, I get a whole new set of issues...
First - the workflow "Re-create SnapMirror and SnapVault Protection after MetroCluster Switchover workflow" doesn't seem to do anything.
Although I have SnapMirror and SnapVault releationships configured on both clusters of the MetroCluster setup, there is only one step performed during execution of above workflow after I performed a switchover:

This in turn leads to - well - nothing...
Second - I get a WFA error when I select the "Re-create SnapMirror and SnapVault Protection after MetroCluster Switchback workflow" without even having clicked on anything within that workflow dialogue:

Kind regards, Niels