  The Very Large Telescope Interferometer Auxiliary Telescopes will soon be
equipped with an adaptive optics system called NAOMI. The corrective optics
deformable mirror is the commercial DM241 from ALPAO. Being part of an
interferometer operating from visible to mid-infrared, the DMs of NAOMI face
several challenges (high level of reliability, open-loop chopping, piston-free
control, WFS/DM pupil rotation, high desired bandwidth and stroke). We here
describe our extensive characterization of the DMs through measurements and
simulations. We summarize the operational scenario we have defined to handle
the specific mirror properties. We conclude that the ALPAO DMs have overall
excellent properties that fulfill most of the stringent requirements and that
deviations from specifications are easily handled. To our knowledge, NAOMI will
be the first astronomical system with a command in true Zernike modes (allowing
software rotation), and the first astronomical system in which a chopping is
performed with the deformable mirror (5'' sky, at 5~Hz).
