[occi-wg] Resource & OS templates retrieving

Hi, My name is John Giannelos and I am currently working on an OCCI implementation. After reading the OCCI specifications, I have a question regarding the Resource and OS templates. After registering each Resource and OS template available, as a mixin related to the categories "resource_tpl" and "os_tpl", how can we retrieve them? The specification says that every OCCI implementation must support a filtering mechanism, which filters the provided categories of the query. But every resource and os template is registered as a category itself, thus cannot be retrieved using this filtering mechanism. I would appreciate some help. Thanks in advance, John