Favities - sweeping tentacles ?

I have small colonies of favia (or favities), brown
variation taken from the seashore of Florida Keys...
They look nice, dark brown with polyps extending
from the rocky ball of their skeleton...
They are doing fine without target feeding, but
I have heard they could benefit from feeding zooplankton
during night - they hunt plankton with sweeping tentacles.
I have inspected these corals at night with a flashlight
and I have never seen any sweeping tentacles...
Here is a short movie of the coral taken during the day
just to show you what coral I am really talking about:
http://www.darmoland.com.pl/pszemol/...6/Favites1.avi
http://www.darmoland.com.pl/pszemol/...6/Favites2.avi
(it might not play directly from the link - then save the
file on your local machine and play it from there...)

So my question would be: anybody here has this or similar
coral in your tank? If so, do you observe sweeping tentacles?
Do you have any pictures of them to share with the group?