  In perturbative QCD, the masses of the hadrons involved in high energy
reactions can usually be neglected. However, in the case of Kaon production in
electron-proton collisions at low (and not so low) beam energies this may not
be a good approximation. In particular, a recent proposal to include hadron
masses in theoretical calculations shows how these Hadron Mass Corrections
(HMCs) can explain a large discrepancy observed in measurements performed at
the HERMES and COMPASS experiments. In this talk, we present preliminary
results of a spectator model calculation designed to test the range of validity
of the approximations needed in the proposed factorization scheme. We focus on
inclusive DIS scattering as a first step towards the analysis of HMCs in
semi-inclusive processes.
