Remove extra space in link and you can download it. I don't know why when I edit post, the extra space is made without reason.
I tried that earlier because I also noticed it and that fixed the problem! Which can I use to activate the Windows Server 2012 R2 DataCenter retail edition? Can Microsoft Toolkit also do that or is that only for the VL edition?
There's no Retail Edition, just a Retail licensing channel. For any Windows since Vista, license channel can be switched by using a key of the desired channel*. MTK will apply a gVLK (VL) key and thus license channel will become VL. You don't need to care about that. *Of course the Windows Edition (aka SKU) must support the desired license channel. All Windows 8.x and Server 2012/2012R2 do support VL(KMS), although not all of them do officially.
#. Windows Server 2003 and Windows Server 2003 R2 Download / A. Windows Server Download / B. Language Packs and Symbols / C. Additional Tools / D. Documents
well you see the spoilers? inside has info for the download (Click "Show"). Anything with magnet:?xt=urn needs a torrent client such as utorrent to use, the rest appear clickable where available. Spoiler