Migrating NBU catalog from Suse Linux master server to an NBU Applianc

Yes, I think this:

The existing NetBackup master server must not be a media server for SharedDisk, OpenStorage or MSDP. Customers should expire or duplicate all copies of disk storage attached to the existing master.

...actually means:

The existing NetBackup master server must not be a media server for SharedDisk, OpenStorage or MSDP.  Customers should expire, or duplicate and expire the copies on SharedDisk, OpenStorage or MSDP, all copies on disk storage attached to the existing master - and remove (i.e. decommission / un-configure) the configuration of SharedDisk, OpenStorage or MSDP.

If I were you, I would log a call with Veritas Support for more details about the steps listed in Article 000087813. 

The assumption is that the Appliance master will be prepared as Master with AdvancedDisk and MSDP pools, but a catalog recovery from another master will wipe out this config.

The article merely says:

The default Appliance configuration ..... will be overwritten.

It does not explain anything about the disk pool configurations and if or how it should be recreated.

Curious to know if anyone has tried this already?

Basically, you're not moving the storage devices, you're moving the catalog. So you should have no storage connected to the master itself. Duplicate off to tape or some other device that is not migrated so it can be referenced after the migration. Then greacefully remove all the storage that might be connected to the master. Then proceed with the migration.