Hi,
For my own, i:
- mount the other storage into a FOG-STORAGE mountpoint,
 - I make a IMAGES directory into it
 - I rsync/copy recursively all /images content into /FOG-STOR/IMAGES
 - i make a symlink /images -> /FOG-STOR/IMAGES
And i do also the same thing for SNAPINS 
Finaly i add lines into /etc/exports to point to the storage (/FOG-STOR/IMAGES/)
I don’t lnow if it’s the best way but it runs very well.
Regards