Server 2008 and custom password filters?

We are preparing to migrate to Windows Server 2008 for our domain. In our Windows 2003 domain, we have a custom password filter and it works properly. When I try to use the same DLL in our Windows 2008 test environment, it does not work. Per http://msdn.microsoft.com/en-us/library/ms721766(VS.85).aspx I have copied the DLL to the Windows (and System32) directory and added the registry key. 

Is there a different procedure for Windows Server 2008? Is the use of custom filters even supported in Windows Server 2008 (I haven't found a definitive answer).

Thanks in advance.