Hi Seth - We are also experiencing this problem, did you manage to find a resolution?
Looks like you are right, as I say we were also trying to do the same thing. But after querying the index created by the FTS in luke, and doing some research and understanding the different attribute types of a lucene field it looks like the Metadata field is just "stored" and not actually indexed.
The metadata field (for blogs & topics (& quite possibly for pageData although I haven’t actually checked)) is used if the EPISERVER_SEARCH_DISPLAY text length is longer than 500 chars... So it’s only the first 500 chars of any type that is searched. You can use the default field but that also contains information about the entity that may not be relevant...
On EPiServers Documentation it describes the Metadata field as "Additional searchable data of “unlimited” size that is not supposed to be returned or displayed together with the search results."
Has anyone managed to successfully index the metadata field?
Has anyone ran into an issue with this, or have any advice on a good place to add the file summary metadata to the index?
Even if this is added manually would FTS query the new fields made to accomplish this without modification?