  We study the growth of galactic disks in live triaxial DM halos. The halos
have been assembled through constrained realizations method and evolved from
the linear regime using cosmological simulations. The `seed' disks have been
inserted at redshift z=3 and increased in mass tenfold over various time
periods, ~1-3 Gyr, with the halo responding quasi-adiabatically to this
process. We follow the dynamical and secular evolution of the disk-halo system
and analyze changes in the most important parameters, like 3-D DM shapes,
stellar and DM radial density profiles, stellar bar development, etc. We find
that a growing disk is responsible for washing out the halo prolateness and for
diluting its flatness over a period of time comparable to the disk growth.
Moreover, we find that a disk which contributes more to the overall rotation
curve in the system is also more efficient in axisymmetrizing the halo, without
accelerating the halo figure rotation. The observational corollary is that the
maximal disks probably reside in nearly axisymmetric halos, while disks whose
rotation is dominated by the halo at all radii are expected to reside in more
prolate halos. The halo shape is sensitive to the final disk mass, but is
independent of how the seed disk is introduced into the system. We also expect
that the massive disks are subject to a bar instability, while light disks have
this instability damped by the halo triaxiality. Implications to the
cosmological evolution of disks embedded in asymmetric halos are discussed and
so are the corollaries for the observed fraction of stellar bars. Finally, the
halo responds to the stellar bar by developing a gravitational wake -- a
`ghost' bar of its own which is almost in-phase with that in the disk.
