RSAT: Enable via Powershell

You can use wusa <path to .msu> /quiet to install the update, then run this powershell script to enable all the features for RSAT.

&$env:systemroot\SysNative\dism.exe /Online /Enable-Feature:IIS-WebServerRole

&$env:systemroot\SysNative\dism.exe /Online /Enable-Feature:IIS-WebServerManagementTools

&$env:systemroot\SysNative\dism.exe /Online /Enable-Feature:IIS-IIS6ManagementCompatibility

&$env:systemroot\SysNative\dism.exe /Online /Enable-Feature:IIS-Metabase

&$env:systemroot\SysNative\dism.exe /Online /Enable-Feature:IIS-LegacySnapIn

&$env:systemroot\SysNative\dism.exe /online /get-features | Select-String -Pattern remote* | %{$Exec = "dism.exe /online /enable-feature /featurename:RemoteServerAdministrationTools /featurename:" + ($_).ToString().Replace('Feature Name : ',''); Invoke-expression $Exec}

&$env:systemroot\SysNative\dism.exe /Online /Enable-Feature:RemoteServerAdministrationTools-Roles-AD-DS-AdministrativeCenter

via Xenophane

Update: If you don't want the SMTP Server Tools installed you can ditch the dism lines that turn on all the IIS components and just run the /get-features line and the AdminCenter line after it. The reason for running Admin Center again is because it shows up in the list before its pre-req so it fails to enable the first time around, so you just enable it again and viola...

Update 2: I modified the script and had the WiseScript call it because SCCM kinda blows. I had to modify the script because calling it with WiseScript tripped the issue with DISM reverting to the x86 version, which errors out, so now it's pointing to the SysNative version (another brilliant idea from microsoft, I guess calling it dism64 or defaulting to x64 and not x86 or about fifty other options made too much sense and therefor had to go).