  We show how a statistically significant signal of heavy charged Higgs bosons
of a general Two-Higgs Doublet Model produced in association with tau-neutrino
pairs can be established at future Linear Colliders in the $H^+\to t\bar b\to
4$ jet decay channel. This signature is particularly relevant in the kinematic
configuration $\sqrt s\lsim2 M_{H^\pm}$, when the pair production channel
$e^+e^-\to H^-H^+$ is no longer available. Here, the initially overwhelming
background, constituted by top quark pair production and decay, can vigorously
be reduced thanks to a dedicated selection procedure that allows one to extract
a signal in a region of several tens of GeV around $M_{H^\pm}\approx \sqrt
s/2$, for $\tan\beta\gsim40$.
