First of all, you need to arrange for the VMs to have access to the same LUN. This is different than a normal LUN allocated to VMWare, as you won't be installing VMFS on it, but instead passing the device through straight to the VMs. This is called a "raw device mapping", and be aware that it will force you to use a different method to move the VMs around among the hosts.
Once both VMs have access to the same LUN, you're ready to start. Unfortunately Windows does not make this situation as easy as it should be. Windows 2008 R2 can't have multiple nodes mounting a Shared Storage Volume simultaneously (except for Hyper-V, which really isn't the same).
What you have to do is setup a Clustered File Share on both servers. One will be the primary file access server, and other(s) the backup(s). You can then mount the network share, or use UNCs, and run the website from that. If you didn't have Shared Storage you'd use DFS-R to duplicate the storage structure on both machines' DAS.
Side note: Server 2012 has CSVs for general purpose access to clustered or NLB'd applications (not all application apply, notably SQL).