I would have, but I never tried the option. Sorry.
Instead; I simply mounted an external drive to /srv/lxc and create my containers there via the Luci interface (for now), as was proposed by Miska. This was/is the most straightforward really (I also used the Luci interface to mount the external drive).
The LXC version on the Omnia is pretty slimmed down (some dependencies even containing bugs), so I try to stay as close to the “Omnia way of working” (that command was copy/pasted from the man page of the regular/Debian LXC package), which until now has not yet disapointed me.