Symptoms

After I run re-configure and enable SSRS (setup completes with no errors)
Open SSRS Manager
Try to add a new DataSource
The DataSource Type dropdown control does not contain SOURCECODE
so I cannot create the datasource.
 

Diagnoses

The issue was caused by missing K2 for Reporting Services component.
 

Resolution

After installing K2 for Reporting Services by running the Setup.exe from the extracted file location with Modify option, customer was able to see the missing SourceCode data source.