  The Accretion-Ejection Instability has been proposed to explain the low
frequency Quasi-Periodic Oscillation (QPO) observed in low-mass X-Ray Binaries,
in particular Black-Hole candidates. Its frequency, typically a fraction of the
Keplerian frequency at the disk inner radius, is exactly in the range indicated
by observations. The variations of the frequency with the disk inner radius
(extracted from spectral fits of the X-ray emission) might thus be a useful
test. In this paper we discuss how changes in the rotation curve, due to
relativistic effects when the disk approaches the central object, affect the
physics of the instability, and thus this frequency-inner radius relation. We
find that the relationship between the frequency of the mode and the Keplerian
frequency at the inner disk radius ($r_{int}$) departs from the one obtained in
a Keplerian disk, when $r_{int}$ approaches the last stable orbit. This might
agree with the recently published results, showing a discrepancy between the
behavior of the QPO in the micro quasar GRO J1655, compared to other sources
such as XTE J1550 and GRS 1915.
  In a companion paper (Rodriguez et al., 2002, hereafter Paper I) we have
presented detailed observational results for GRO J1655 and GRS 1915. We show
how the opposite correlations found in these sources between the disk color
radius (assumed to be close to its inner radius) and the QPO frequency could
indeed be explained by our theoretical result.
