Actually, there's a significant difference between the way RioRid works on the Central than on the Empeg. But it's smart enough to know the difference and it Does The Right Thing when it detects it's talking to a Central.

The difference is...

On the Empeg, and on the Karma, the RID is an additional "RID" tag all its own, stored in the FID file that contains the database information.

The Central, for some reason, can't add custom independent tags the way the Empeg/Karma can. If you send the commands to the Central to add a custom tag, it won't stay. So you can only update existing tags. So what Mike does on the Central is he stores the RID in the existing "Comment" field. And then when it comes time to backup/restore playlists with Riobackup.jar, or when it comes time to copy/paste playlists in Jemplode, he checks both fields for the RID.