I found this Blog recently.  It belongs to Chris Webb another of our new SQL Server MVPs.. 

Chris has mentioned in his blog about Reporting Services and server aggregates and raises an interesting issue ‘adding an explicit switch that allows treating server aggregate rows as "detail rows".’What do you think? 

Here is his MVP profile
Chris has been working with Microsoft BI tools since he started using beta 3 of OLAP Services back in the late 90s. Since then he has worked with Analysis Services in a number of roles (including three years spent with Microsoft Consulting Services) and he is now an independent consultant specialising in complex MDX, Analysis Services cube design and Analysis Services query performance problems. His company website can be found at http://www.crossjoin.co.uk and his blog can be found at http://spaces.msn.com/cwebbbi .