Setup up SQL 2008 r2 sp1 French for Scom 2012 sp1 English.
Scom needs Builtin\administrators during setup to populate user roles in SQL to create its DB.
SQL french will accept Builtin\administrators (from AD) in security connection and save it as Builtin\administrateurs
SCOM cannot continue setup because it needs Builtin\administratorsnot Builtin\administrateurs