model of A06 the dependance of the X-ray emission on the primary mass loss rate is $L_x \sim \dot M_1^{1/2}$. Namely, it is quite possible that the primary mass loss rate, and hence $N_H$, were higher than the average value near apastron by a factor of $\sim 1.25$, and this is the reason H07 did not find the column density to increase between phases $0.47$ ($-0.53$) and 0.92 ($-0.08$).

Another effect not considered by us, and that introduces more variations, both in the time variation and in the absorption by the conical shell along different directions, is the corrugated structure of the shocked primary wind that results from instabilities (Pittard & Corcoran 2002; Pittard et al. 1998; Okazaki et al. 2008; P09).

As mentioned earlier, from behind the secondary shock (namely, if the secondary is toward us near apastron), it is not possible to account for $N_H=17\times10^{22} \cm^{-2}$ column density near apastron. It cannot come from the nebula, as the nebula can supply $5 \times10^{22}\cm^{-2}$ at most, as deduced from the column density toward the low temperature gas (the extra soft component, H07). Also, from figure 2 of P05 we learn that when the system is at apastron, there is 