Presently, if you have installed ConfigMgr 2012 with SQL Server 2008 R2, and attempt to edit a report from the console, you will get an error message that states “Report Builder not available”. The problem here, ConfigMgr 2012 is designed to work out of the box with Report Builder 2.0 as explained here:
Since you have installed SQL Server 2008 R2, which ships with Report Builder 3.0, you can indeed use Report Builder 3.0, just open it directly from SSRS Report Manager.
While not supported or endorsed by Microsoft, a workaround is available to integrate RB 3.0 from the console, as follows:
You’ll need to set a registry key to name the RB 3.0 application manifest. The key in question is “HKLM\Software\Wow6432Node\Microsoft\ConfigMgr10\AdminUI\Reporting\ReportBuilderApplicationManifestName”. Change its value from “ReportBuilder_2_0_0_0.application” to “ReportBuilder_3_0_0_0.application” on any machine from which you want to launch RB 3.0.