in Simpana V10, a Windows MA was needed to decode the Backup for granular recovery.
In case of (only) Linux MAs in your Environment, you could also use the CommServe, or any other Windows MA (even without access to the library) to restore the data.
with V11 support for Linux VSA is being announced (if remember correct), so maybe you can also use a Linux MA for restore.
You could also add MA Software to the VSA and address this one as MA for the Restore. (as mentioned, no direct access to the Library is needed)