Hi Bren,
I don't know the actual answer to your question, but I believe you can use a mount point:
1) Move all the content of "C:\Program Files\NetApp\SnapManager for SQL Server\Report" to somewhere else
2) Once the folder is empty, use it as a mount point for your LUN
3) Move the legacy data back into the folder
Should work IMHO.
Regards,
Radek