Rather than building an Ifilter to index all the data created by my application, I like to have a method to resolve the queries against my module's own index instead and present the result back to WDS for presentation.
This one may already on your future release already since Google is providing a similar function via their OneBox API. If it is, please give us a sense of the timing for such release. Thx!
Keep an eye on the forum for Windows Live Search Center. It is a new product that will be released in beta form in the near future. Our goal is to have it provide the kind of functionality you are looking for.