Cluster - "Add all eligible storage to cluster" checkbox missing?

I am following this tutorial to setup SQL HA Always On in Azure and it advises to uncheck the "Add all eligible storage to the cluster checkbox on the Confirmation page".

Tutorial: https://msdn.microsoft.com/en-us/library/azure/dn249504.aspx

I am using storage spaces and wanted to follow that advice, but that check box does not appear.

There is simply nothing there on the Confirmation screen.

Has anyone else encountered this, I assume I must be missing something?

This is Windows Server 2012 R2 that I am using.

Thanks