What that article states is that you cannot redirect the restore and it must go back to a volume with SIS enabled - it also points you to the Microsoft KB as it is not a Backup Exec limitation.
In practice what it means is if you lost the whole SIS environment you would have to rebuild a server with same name and same drive letters and possibly volume labels on the drives, then re-enable SIS on the volumes before attempting to restore the data. Of course this very process will extend the total time to have your data back compared with just being able to redirect to somewhere in a hurry if SIS was not involved.
One workaround to this is to open up share level backups from the volume root, as this type of backup whilst slightly slower and potentially using more space in your backup media, backs up the data as an end user sees it instead of as the file system sees it.
Another option is to possibly think about using Windows 2012 Deduplication instead of SIS.
Note: It is possible that we will shortly be adjusting existing or providing new articles relating to the recovery of SIS as we are actually in the process of researching a condition relating to SIS recovery.
