To avoid regression testing I recently had to build a web role with a minor bug fix using Azure SDK 1.8 and Visual Studio 2012 even though SDK 2.2 and Visual Studio 2013 are the latest versions.
I created a Hyper-V VM and it was easy enough to installed Visual Studio 2012. Getting Azure SDK 1.8 was a little harder until I figured out this command:
webpicmdline /Products: WindowsAzureToolsVS2012_1_8 /AcceptEula /xml:https://www.microsoft.com/web/webpi/4.1/WebProductList.xml
The trick was finding the right WebProductList.xml. I used:
webpicmdline /list:all /xml:https://www.microsoft.com/web/webpi/4.1/WebProductList.xml
and kept increasing the 4.1 part of the URL until I found a version that contained the product I needed.