When performing an FLR of a server using Storage Spaces drives are not listed in the Backup Browser.
The properties of these disks will appear as Microsoft Storage Space Device.
Storage Spaces volumes are not supported for file level recovery.
Consider using Instant VM Recovery to recover guest files from such VMs. See: http://www.veeam.com/kb1459
As a long term solution to allow the FLR to work as expected considering moving the data off the storage spaces drive to regular single VMDK backed drive.
Note that Microsoft does not support Storage Spaces within a VM.
Please be aware that starting from September 2018 downloading updates will require an active contract for the corresponding product.