I'd like to echo this curiosity...

I had the impression up to this point that the current version of eQuest
can effectively model a photocell, using the defined vector
placement/orientation.

Here's an applicable entry in the help files that supports this notion:

LIGHT-REF-POINT1, LIGHT-REF-POINT2

Takes a list of three values that gives the x, y, and z coordinates (in
the space coordinate system) of the reference points at which daylight
illuminance levels are to be calculated. If DAYLIGHTING = YES, then
LIGHT-REF-POINT1 must be specified. If you want to divide a thermal zone
installed lighting kW into two independently-controlled daylighting
zones, then LIGHT-REF-POINT2 should also be specified. It is assumed
that the photocells that control the electric lighting system respond to
the light levels at the specified reference points.

Should we not be thinking of these vectors as placement criteria for the
a photocell controlling the daylighting controls?

NICK CATON, E.I.T.