I unpacked my Old style NX-250 to see if it would be possible to retrofit the velcro needed above the pockets to fit the new style Z-liner. It seems to be do-able. The only slight problem I see, is that the foot end piece of velcro on my model, is aligned with the top of the pockets. So if you add the needed velcro you'll either have to add it full length of the entire hammock, leaving double velcro side by side at the foot end, or live with the fact that you'll have a small "step" in the velcro from the foot end part to the pocket part of the hammock.
It's a bit hard to explain with words, so hopefully this video will make a bit more sense of it