although not having much experience with PHP and programming in general I think/hope I somehow made it to extend the OAI-PMH repository plugin in such a way that it is now possible to export also the Dublin Core Extented element refinements as well as stand-alone elements).
As a starting point I used the short manual that comes with the plugin.
After that I studied the OaiDc.php file in the /metadata folder of the plugin and used it as a template.
Furthermore I tried to follow the Guidelines for implementing Dublin Core in XML as close as possible.
Here is the result: https://gist.github.com/3187492 (every piece of code written by me has a comment starting with NEW)
Some Examples of the output can be found here:
One unsolved issue concerns the Open Archives XML namespace and schema for the output format which is currently tailored to the Dublin Core Simple Fields and completely excludes the DC extended fields. I think I have to create a new one but I still have to look into that.
It would be great if you can have a look at this and tell me if I'm on the right track here or not.
Regards, Matthias Einbrodt