Hi. I've just contacted Adobe about this feature request and
have been told that the SALIdxSvc12.xml file in your install folder
can be edited to exclude the baggage file types that you DO NOT
want indexed. If you backup this file and open it in Notepad,
you'll find a line like <Type Ext=".pdf"/>. If you remove
this line (or <Type Ext=".doc"/>, <Type Ext=".docx"/>,
etc.) from the file, and save it, baggage files of this type are
excluded from being the search. You'll need to relaunch RH to pick
these changes.
The only proviso for this is that you should only remove file
types not add them! Hope this helps as a workaround.