I do not take credit for creating this, only uploading.
This is a workaround to get Heart of the Swarm working on a copy of Wings of Liberty. Follow these instructions exactly and it SHOULD work.

"READ ALL BEFORE CONTINUING. DO NOT SHOOT YOURSELF IN THE FOOT LIKE I DID TWICE

1: Get a working copy of WoL, fully patched to 2.0.6. (this can be a cracked copy or legit copy)

2: In your Starcraft II directory, COPY AND DELETE the Updates folder, and in the Versions folder, COPY AND DELETE Base24944 folder. You want to have these copied somewhere as a backup, just in case. Redownloading this whole game is a pain.

3: Paste from the 2.0.5 downgrade folder the folders you just deleted.

4: Paste the Heart of the swarm save file in your saved games folder (located in your documents usually)

5: Block all blizzard related applications in your firewall OR (and this is what I did) just disconnect your computer from internet when playing. DO NOT ATTEMPT TO HAVE SC2 CONNECT TO INTERNET. IF IT STARTS TO PATCH YOU HAVE DONE SOMETHING WRONG

If these are followed, you then can play by simply:

1: Opening SC2 without internet. To do this you must first have connected to a b.net account in order to play in offline mode.

2: Go to campaign and select LOAD GAME

3: Find the heart of the swarm save

4: Load it, and then go to menu and exit game, chosing to replay mission from start.

Congrats, you can now play the campaign of Heart of the Swarm. I really don't recommend connecting to B.net&