Is there any documentation for creating custom search crawlers for the new Lucene search?

I've been shooting in the dark, but so far I've copied the TabIndexer, hardcoded a list of test SearchDocuments in and added that class to the web.config searchIndex section.

I was expecting this to register my indexer so it was run when I hit the Reindex button, and my hardcoded text to then give some kind of search results, but nothing. No errors in log, and logging in the indexer gives nothing.

Any pointers? Am I even slightly in the right area?