Install Forefront on Domain controller

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http://serverfault.com – I have a problem on installing Forefront on domain controller. After googling bout this, I found that just forefront SP1 can be installed on DC. but I have Forefront (not SP1). So I decide this : 1 - First install Forefront 2 - install Domain Controller 3 - Upgrade my installed forefront to SP1 am I correct ?!! Sorry an other question is about installing forefront : After installing forefront I got an error during installation , I got an error about SQL Server, So . Is it better to install MSSQL Server 2008 R2 by myself?!! Thanks (HowTos)