If an user embeds a word document within another word document, we would like to retrieve results in the Confluence's search from the inner document (embedded in the the outer word document).

In this situation, we have a word attachment with an "inner document" embedded into an "outer document". (the attached file "doc_O.doc" contains "this is the outer document" and when you open it you will see it contains "this is the inner document" as an example)