Registering URNs

Hello all,

I have the following problem in OJS 3.3.0.8

We need to give an URN to a cartoon (we usually give DOIs to articles). So I installed and configured the URN plugin as can be seen below:

URN1
URN2

As I found no guides on this, the settings are a bit hazy, but I managed to include the URN to the cartoon page. The problem is that it is not shown in the OAI-PMH -feed (of a partner library), so it is not registered. Any ideas on what the problem is?

Thanks, Markku