Thanks for you answer.

VMware support also suggested the VMware Cloud Director Availability (VCDA).
It is a pity that the VCD has not integrated this directly itself.

Some other ways could be (not tested):
* Convert the VM to a vApp template, place the template in a catalog, subscribe the catalog on the other side and then deploy the template
* Convert the VM to a vApp, download the vApp as OVA and import the OVA on the other side
* Other 3rd-party tools like Veeam