2005 Scatter Chart won't run on 2008 server?

After a recent upgrade from SSRS 2005 to 2008, we discovered that any reports with scatter charts will no longer render any points when running in 2008.  Apparently the upgrade process doesn't modify these.  I can pull a report into VS2008 and modify it so that it will work correctly, but we have a number of devs that have not  /cannot upgrade and are continuing to work in VS 2005.  I can't find any MS documentation that says 2005 scatter charts aren't supported on a 2008 server.   In this artcle:http://msdn.microsoft.com/en-us/library/ms143674.aspx it makes mention of running reports in backward-compatibility mode that can't run in 2008; according to the execution log though these scatter charts are running in 2008 (they run, just not correctly).  Anybody know if you can manually force a given report to run in backward-compatibility mode?  Anyone have a simliar challenge with older scatter charts?

thanks