Where are CustomPress posts, taxonomies etc. stored?

Hi,
I previously created some custom post types and taxonomies using another module. I want to remove this module and use CustomPress instead. When I installed CustomPress I hoped that the existing custom post types, taxonomies and fields would show up in CustomPress, but they don't.

I've tried creating some custom post types and taxonomies using Custom Press and can't find where they are stored in the database.

Can you enlighten me? It seems like none of it is actually stored in the database. Is it stored elsewhere?

Thanks for your help.
Tim