Information in custom fields can be reflected from one workspace to another by exporting the workspace as a spreadsheet and then importing it in via the Import button.
When exporting the original workspace, you'd need to ensure that the owner of the workspace has given you edit permissions for that field. Then make sure that the custom field is added in chosen fields.
This should then show in the downloaded spreadsheet:
Then delete all other fields in the exported Workspace and leave just the Publication Number and Comments fields:
Then once you import this back into PatSnap it should show up as below.