Hi Tomt,
The question you asked is essentially for security on report model, since
Report Builder is just a report making tool like BIDS, while report model
is the underlying data source which you need security settings for restrict
access by users/roles.

I recommend that you refer to the following article in SQL Server Books
Online that amply addresses this topic:
Securing Models
http://msdn.microsoft.com/en-us/library/ms156505(SQL.90).aspx

Hope this helps. If you have any other questions or concerns, please feel
free to let me know.

Best regards,
Charles Wang
Microsoft Online Community Support
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Hi Tom,
Just a kind reminder, I have not received your response. Please feel free
to post back at your convenience if you need further assistance.

Have a great day!

Best regards,
Charles Wang
Microsoft Online Community Support
=========================================================
Delighting our customers is our #1 priority. We welcome your
comments and suggestions about how we can improve the
support we provide to you. Please feel free to let my manager
know what you think of the level of service provided. You can
send feedback directly to my manager at: msdnmg@microsoft.com.
=========================================================

=========================================================