  We investigate the azimuthal distribution of quark-antiquark jets in DIS
diffractive dissociation with large transverse momentum. In this kinematical
region the matrix element is expressed in terms of the gluon structure
function. For the transverse part of the cross section we find a $\cos(2
\phi)$-distribution with the maximum at $\phi = \pm \pi/2$, i.e.\ the jets
prefer a direction perpendicular to the electron plane. This is in contrast to
boson gluon fusion where the $q\bar{q}$ jet cross section for transversely
polarized bosons peaks at $\phi=0$ and $\phi=\pi$. We discuss the origin of
this striking difference and present numerical results relevant for the
diffractive dissociation at HERA.
