This is confusing to think about, but I think it is unfortunate these have become divided. 

The basic implementation of `to_semantic_values` uses Solr stored fields too. So what we have now, is you need to configure one place, `to_semantic_values`, for (eg) which Solr stored field corresponds to 'author' for it to be included correctly in (eg) the atom response or the dublin core XML output; and you need to configure the same thing, which Solr stored field corresponds to 'author' in another place for it to be properly tagged with schema.org stuff on the display. 

This is unfortunate right?  I don't understand what's going on enough to know the solution, but it seems like maybe possibly the default stored-fields-based `to_semantic_values` implementation ought to be changed to use the same configuration this schema.org stuff is using -- or vice versa. 

The `to_semantic_values` default stored-field-based implementation appears to use use a `field_semantics` class method on Solr document, a hash from symbol representing a meaning (like :title) to a stored field name.