I have a customized Force.com site and Customer Portal working together.  The portal users are High Volume Customer Portal users.  There are some pages that require no authentication (i.e., public/guest) and some that require authentication.  

I'm having an issue where the authenticated user cannot see Documents files (e.g., a pdf) , even though the guest/public user can.

Here's what's happening:

1. A user comes to the Force.com site as a guest/public user and can click the link that was created with apex:outputLink with a value of "/servlet/servlet.FileDownload?file=<recId>" and see the pdf because I set up sharing on the folder that the file is in to include the Guest User.  No problem.  

2. User logs in becoming an authenticated High Volume Customer portal user.

3. User clicks on that same link and now they get a Insufficient Privileges error.  PROBLEM!!!

According to http://login.salesforce.com/help/doc/en/customer_portal_manage_users.htm the High Volume Portal User cannot be included in any sharing rules, so there is no way to share this document with them (as far as I can tell); however, it seems like there *should* be some way for them to view it since the use case I've described seems completely reasonable that if the whole world (i.e., guest user) can see the document the authenticated user should be able to as well.

Both the portal profile and the guest/public profile have Read CRUD set on the Documents.

How can I get the authenticated High Volume Portal user to be able to see the Document?  I feel like I must just be missing something obvious, because I can't see how this wouldn't be supported.

If there is no way then what is the recommended way to handle this situation?

Thanks.