Binding to AD fails with a .local domain

Hi folks,

ACMT here, but brand new to the server side of things, so please forgive my lack of familiarity with some of this stuff.

I am working with a company that is rolling over to a Windows 2008 domain configuration from a workgroup config. The domain is a .local TLD, which I understand can cause issues with OS X. Windows machines have had no issue being added to the new domain, but any time I try to add one of the iMacs, it fails. I have tried adding from the "Join" dialog under Login Options as well as from Directory Utility. I get one of two error messages every time - either a simple "Unable to connect to server." or "Unable to add server. Node name wasn't found. (2000)" regardless of which method I try. Windows recognizes the domain with just domain or domain.local, and I have tried both of these, as well as the FQDN and IP address of the server. It doesn't make a difference.

I'm running 10.6.8, 10.7.5, and 10.8.5 at this location. I've still got another location to roll over, but there's a lot more iMacs there and I want to get these three figured out before I start on those. Unfortunately I'm unable to update the OS on any of these, as there are certain limitations of some of the software they are using here, which there's no way around. We have no Mac servers, or I'd just set up OD to play with AD and be done with it (at least, that's my understanding of how that would work). I'm also curently unable to change the TLD to a .com or something, though I have asked the higher ups about it.

I've added the correct DNS IP addesses to the DNS tab on the network connection, as well as added domain.local to Search Domains. I've checked (and corrected) the time on the server so that workstations and server match. I've reset the PRAM, which I understand has no network settings on newer setups, but I'm trying every suggestion I can find at this point, shy of modifying/creating settings on the server that I know next to nothing about. I've looked at http://support.apple.com/kb/TS4041, which may fix the 10.6.8 machine, but because I'm running 10.7.5 and 10.8.5 on the others, this shouldn't be an issue, right?

Near as I can tell, I have three things left to try. 1) Change the domain.local to domain.com or some other valid TLD. 2) Getting someone to modify the correct setings on the server, as described in http://support.apple.com/kb/TS4041. 3) Grab some software like ADmitMac (https://www.thursby.com/products/admitmac) and hope that fixes it. There's also the hack that basically reduces the mDNS timeout to near-zero, but I don't know how that may impact everything else using Bonjour and don't want to mess with that when it appears to have been addressed in newer versions of the OS.

So my questions are: Have I missed anything? Has someone here run into a similar situation and have any suggestions? Is ADmitMac really a viable solution? Is the .local part actually the problem here, as my research has led me to believe, or has that effectively been solved on anything running 10.7.3 or newer?

Thanks in advance. I know it's a mess.