I have done some research on this issue in the past as I would love to use LogonStudioVista with x64 WS2008 but have failed so far.
I think what you may be running up a gainst is WIndows Resource Protection (http://msdn.microsoft.com/en-us/library/aa382503.aspx), which in short prevents any changes to a protected list of installed programs, which this dll is one of. I have experienced replacing the file (even under safe boot), and finding the system quickly replaces it back! You need to use a particular set of APIs, that for example Windows Installer uses, to make a file change stick.
I concluded to myself this was the issue, there in fact may be even more robust protection under Windows Server 2008 x64 but I can’t remember now as its been 6 months since I researched this.
Good luck if this helps you make some progress!
Yeah Windows XP has a similar thing called System File Protection (SFP) where if it detects a changed dll it grabs the original out of the hidden dllcache folder and replaces it pretty much straight away… for some reason they removed it in Vista/2008 x86, maybe UAC was the replacement, but it looks like x64 has it instead now… strange.
I really should get my hands on an x64 copy, now that I can run it, to try and figure this 64-bit trouble everyone has…
EDIT: This guy has written a detailed post on how to resource hack DLL’s in Vista x64, namely how to bypass Windows File Protection [WFP] which apparently is in x86 (but I didn’t have to turn it off to replace it!?!)
Hopefully that helps.
EDIT2: Basically that guy is just replacing DLL’s from his x64 Vista while in a x86 Vista [dual boot], doing it to both the system32 DLL and the SysWOW64 dll. This is how I remember it exactly aswell, so I don’t see what the problem is. If you can’t install a second x86 Vista/XP to replace the DLL’s in, check out BartPE at http://www.nu2.nu/pebuilder/
Someone must have a way to replace x64 DLL’s more easily. Sadly I can’t find one.