I have installed Sql Server 2008 & 2012 side by side on the same machine, and that's includes the reporting service for each. Both are instances are named instances: MSSQLSERVER2008 and MSSQLSERVER2012.
I didn't configure the 2008 one but configured 2012 first and this one is working fine. However later on when I wanted to configure the 2008 reporting service instance I was not able to do so; it simply cannot find it.
Both services are displayed as running, nevertheless while being in Reporting Services Configuration Manager only the 2012 instance is displayed.
I tried stopping the 2012 but still no luck, 2008 won't show up in the RS configuration manager.