[dba-SQLServer] Upgrading SSRS 2005 To SSRS 2008 On Different Server

To all,

I am getting an error when reports have been migrated from SSRS 2005 to SSRS
2008 which is
'The data source 'Connection_To_AL_SQL_Genesis' cannot be found.  The data
source name in SSRS 2005 is actually
'Connection To AL-SQL Genesis', I looked around on the internet and
apparently when migrating to SSRS 2008 any spaces and hyphens in the
connection name get replaced by underscores.  So I went back to the data
sources on SSRS 2005 and renamed my connection to
'ConnectionToALSQLGenesis' and relinked all the reports to the new name.  So
then went through the process of backing up the reportserver and
reportservertempdb databases, and the reporting services encryption keys,
copied the files to the new server, restored the databases and the reporting
services encryption keys.  However I am still getting the same error message
when trying to open the reports, if I go to the properties of the report and
re-connect to the data source I still get the same error.  However if I
reload the report and connect to the data source then it works !!!!!

Can anyone shed any light as to what I am doing wrong or what I need to do
to resolve this, as I dont really want to reload all the reports and
re-connect the data sources.

-- 
Paul Hartland
paul.hartland at googlemail.com