It's still a separate DLL as Les said. The only official package that contrains it is the ADSI SDK 2.5 which can be found here: http://download.microsoft.com/download/2/9/7/29720925-faa3-477f-a5cd-beef80adac07/adsrtk.msi

But after months of trying every other ACL modifying program such as CACLS.exe, XCACLS.exe, XCACLS.vbs, SetACL and more I believe AdsSecurity is the best choice for scripts.