If I understand the question correctly, you want to create a SQL cluster out of two VMs running inside Hyper-V on Windows Server 2012 Hyper-V hosts, correct?
In order to use shared disks (which you need) you have two options:
1. Virtual Fibre Channel
Virtual fibre channel lets you take an existing SAN and present it to a VM much the same way as you present it to a physical host. There are a few prerequisites though, so your SAN might not support this. A good description can be found here: Hyper-V Virtual Fibre Channel Design Guide
For iscsi, you can simply present your SAN as an Iscsi target to the clients. Your SAN might be able to do this natively, or you might need to present the SAN to some kind of NAS which again makes the storage accessible through iscsi. Windows Server can do this, and I'm sure any linux distro can do this as well.
Edit: Using Hyper-V in Windows Server 2012R2, which is just around the corner, you can implement shared vhdx diskfiles, as long as the vhdx resides on a SMB3 shared folder. This is described here:
How does the shared VHDX file feature in Windows Server 2012 R2 work?