ACROBAT CATALOG INDEX NOT BEING USED

We publish print catalog, and now are starting to publish (as PDF files) on CDs as well.
 
Using Acrobat Professional 7 to author, an Acrobat Catalog Index is generated for fast searches. We then put the PDF file an index files on a CD using HTML-based menu.
  
The Search works fine if the PDF files are opened directly in Acrobat Reader (independent of the browser). However, since we are using a HTML-based menu, depending on the users' browser preference, the PDF, most of the time, is opened within a web browser. The problem is that if the PDF is opened within a web browser, then it DOES NOT and CANNOT seemt use the index. This nullifies the included index. Search is much slower.
 
Is there a way around this?
 
If the HTML-based menu is the culprit, then is there a way to force the Acrobat Reader to be launched independently of the web browser.
We would like to retain the menu interface to make it easier for the CD users to explore the CD content.
 
Any information would be greatly appreciated.
 
Thanks!
 
Immanuel