Hydrogen pick-up ions produced in the inner heliosphere are convected outwa
rds with the solar wind and suffer energy-diffusion by quasilinear wave-par
ticle interactions. When arriving at the solar wind termination shock, the
big majority of these pick-up's passes directly from the preshock to the po
stshock plasma regime. While crossing the shock these ions suffer a charact
eristic change in their density and velocity distribution which sensitively
reflects the local shock properties. We extend the earlier model calculati
ons to derive the pre-shock and postshock pick-up proton spectrum in the ec
liptic plane, taking into account the global structure of the heliosphere a
nd the termination shock. The proton distribution is used to calculate the
energetic neutral hydrogen flux and the results are compared with the CELIA
S/HSTOF data. There is a satisfactory agreement as regards the flux intensi
ty scale and the directional dependence of the flux. The calculated energy
spectrum is steeper than the data.