  We model the correlated X-ray - UV observations of NGC 7469, for which well
sampled data in both these bands have been obtained recently in a
multiwavelength monitoring campaign. To this end we derive the transfer
function in wavelength \ls and time lag \t, for reprocessing hard (X-ray)
photons from a point source to softer ones (UV-optical) by an infinite plane
(representing a cool, thin accretion disk) located at a given distance below
the X-ray source, under the assumption that the X-ray flux is absorbed and
emitted locally by the disk as a black body of temperature appropriate to the
incident flux. Using the observed X-ray light curve as input we have computed
the expected continuum UV emission as a function of time at several wavelengths
(\l \l 1315 \AA, \l \l 6962 \AA, \l \l 15000 \AA, \l \l 30000 \AA) assuming
that the X-ray source is located one \sc radius above the disk plane, with the
mass of the black hole $M$ and the latitude angle $\theta$ of the observer
relative to the disk plane as free parameters. We have searched the parameter
space of black hole masses and observer azimuthal angles but we were unable to
reproduce UV light curves which would resemble, even remotely, those observed.
We also explored whether particular combinations of the values of these
parameters could lead to light curves whose statistical properties (i.e. the
autocorrelation and cross correlation functions) would match those
corresponding to the observed UV light curve at \l \l 1315 \AA. Even though we
considered black hole masses as large as $10^9$ M$_{\odot}$ no such match was
possible. Our results indicate that some of the fundamental assumptions of this
model will have to be modified to obtain even approximate agreement between the
observed and model X-ray - UV light curves.
