Reusing a Selfsigned cluster certificate from one cluster to another

Good afternoon,

While working on hybrid prototype which would be compounded of 2 clusters, 1 on premise, 1 on AWS, we would like to export on premise self-signed and import it into the 2 cluster.

Is there a simple way to do it?
Tried to import using ssl-manage --upload-cluster-ca which worked fine.
But Couchbase do not seem to appreciate it.