I know this is really old, but consider using the Custom Metadata Panel, which works in Premiere Pro.  ... View more

Hi Doug. CMP author here. We partnered with IPTC to include a Tab that IPTC made, so it's completely compliant with their spec, including pre-defined properties. They've included a Photo and Video version, too. Update to version 2.0.5 to get the latest.  You can now create new Tabs without loading JSON, too. See the new Tab Manager below. ... View more

For this use case, consider using the Custom Metadata panel. It supercharges metadata in Photoshop, Premiere Pro, Illustrator and even Bridge. You can easily create custom metadata forms (no XML required!) using pre-built tabs or make your own. CMP properly supports Structures and language alternatives, too! Admins can create and share panel definitions via JSON or host them at a URL for central management. It's the bomb. ... View more

If you want to access custom metadata properties, consider using the Custom Metadata Panel extension. It works in Premiere Pro, Photoshop (in Rosetta 2), Illustrator and Bridge. You can create custom forms that include XMP and Clip metadata, sync Clip metadata with XMP, and expose custom XMP properties that the Premiere Pro Metadata Panel can't show. It also supports metadata Presets. Forms and presets are shared between Pr, Ps, Ai and Br.  https://exchange.adobe.com/apps/cc/103752/custom-metadata-panel ... View more

You might consider starting with the BOLT CEP framework. It takes the voodoo out of setting up a project and lets you get straight to coding.  https://github.com/hyperbrew/bolt-cep ... View more