  The diffractive production of open charm in deep-inelastic scattering is
studied in the semiclassical approach which has been proposed recently. In this
approach, the leading order process contains a charm quark pair and an
additional gluon in the diffractive final state. The $p_{\perp}$-spectrum and
the diffractive mass distribution are evaluated and compared with predictions
based on perturbative two-gluon exchange calculations for charm quark pair
production. It is shown that the $p_{\perp}$-spectrum provides a clear test of
the underlying partonic process whereas the diffractive mass distribution
reflects the non-perturbative mechanism of colour neutralization.
