SQL Server 2008 in Windows Server 2008 R2 (SlipStream method)

During these days i have tried to install SQL Server 2008 Failover cluster in Windows Server 2008 R2 but i have faced many problems when i try to install SQL Server 2008 with SP1 or SP2 and these error like "There wan an error setting private property RequireKerberos to value 1 for resource ..." , "Network Name already exists" so i search for the solution in the internet and i found this is way to fix the above problem by using SlipStream method
http://blogs.msdn.com/b/petersad/archive/2009/03/02/sql-server-2008-basic-slipstream-steps.aspx
http://blogs.msdn.com/b/petersad/archive/2010/10/14/creating-a-merged-slipstream-drop-containing-sql-server-2008-rtm-and-service-pack-2.aspx

and these are the steps for basic Slipstream :
Extract SP1 to folder c:\SP1 by using this command

SQLServer2008SP1-KB968369-x64-ENU.exe /x:C:\SP1
then run MSI file go to C:\SP1\x64\setup\1033\sqlsupport.msi
finally run this command
setup.exe /PCUSource=C:\SP1 and continue as normal steps.
Done