  We estimate the upper frequency cutoff of the galactic white dwarf binaries
gravitational wave background that will be observable by the LISA detector.
This is done by including the modulation of the gravitational wave signal due
the motion of the detector around the Sun. We find this frequency cutoff to be
equal to $10^{-3.0}$Hz, a factor of 2 smaller than the values previously
derived. This implies an increase in the number of resolvable signals in the
LISA band by a factor of about 4. Our theoretical derivation is complemented by
a numerical simulation, which shows that by using the maximum likelihood
estimation technique it is possible to accurately estimate the parameters of
the resolvable signals and then remove them from the LISA data.
