Enterprise/Pro editions uses a completely different activation technique. Doesn't use OEM SLIC info. If U use the Microsoft Toolkit that is in your link you will be able to activate Enterprise using the AutoKMS of the toolkit. Use the version 2.3.2 of the toolkit and select EZ activator for Windows. I have done this many times without problems for both Enterprise and Pro versions.
@ MonsterMMORPG, I would forget enterprise if you have oem:slp 2.1 just install Ultimate for permanent activation.
Forget Enterprise edition, just Install Ultimate and activate via SLIC 2.1 by Windows Loader or Manual activation. Ultimate is the same exact as Enterprise 34 different languages and all; only difference is the way it activates. Ultimate uses OEM:SLP, OA, or Retail key versus Enterprise that activates via KMS or MAK key.