Backup Exec Private Cloud

Hello 

We are looking for Symantec Backup Exec private cloud for our customers, I have been reading though the Backup Exec 2014 Technical White Paper Private Cloud Services & Planning and Deployment Guide.  My question is, does it mandatory to use OST supported storage devices at Manaaged Service Provider Backup Exec and the customer Backup Exec Servcer environment as disk repository ? or can we use any storage disk and Dedupication Option license on both ends?

Thanks,

Ragesh