Oracle publish an Excel file named "Certification matrix" which provides all these info: http://www.oracle.com/technetwork/middleware/fusion-middleware/documentation/fmw-1221certmatrix-2739738.xlsx
In the "Database" sheet you can filter on "Microsoft SQL Server" as "Database Vendor" and you find your answer:
Oracle Business Intelligence Enterprise Edition FMW 220.127.116.11.0 Microsoft SQL Server 2008 R2; 2012; Application Datasource WebLogic JDBC Driver for Microsoft SQL Server Type 4 1. Types of Database Use: Repository and Datasource
2. For Microsoft SQL Server 2012, SP1+ is supported.
So yes it's supported as source, but it's not supported as DB for the RCU, for that you will need 2012.