A. As of Windows Server 2008 R2, the CSV feature is for Hyper-V use only. When you enable CSV, you have to acknowledge a statement that reminds you that CSV is only for Hyper-V. This means it's not supported to create a file share on a CSV volume, and the folder sharing graphical interface will block attempts to create a share. There are ways to create the share usinhg the Properties of the folders Advanced Sharing option, but this will make the entire failover cluster unsupported.
Why is this suddenly an issue? XenDesktop 5 has a step that requests that sharing be enabled on your CSVs if you're managing with System Center Virtual Machine Manager you have the Use XenDesktop to create machines option enabled in the Desktop Studio wizard. This requirement conflicts with Microsoft support. Once I have any kind of final word from Citrix I'll post an update.