First: I don't know the game. All I know is from this page: http://www.scssoft.com
, where several versions of "hunting unlimited" games are listed.
But you say it uses the PMG/PMD format. Even if you are talking about the last one of these games, which I think is "Hunting Unlimited 2010" from year 2009, this will be different than the actual PMG/PMD format. That format has changed several times, over all these years. A PMG of 2009 has a different structure than a PMG of 2012. It changed even with ETS 2 version 1.4.
I don't think blender2scs will be able to import this correctly. Because it was written to support the PMG format of ETS 2, not for the older stuff, like you already said.
In those days the tool for working on SCS models was Zmodeler 2. But I know only of people using it for the truck games, not the hunting games. I have no idea how much was possible with Zmodeler 2, then, for your request, but I know that there where converts of hunting models to the truck world. Long ago, and whatever that means. Maybe it was tricky even then.
Conclusion: This will get difficult if you are not experienced in modding of older SCS games. In those days assistance by SCS for modding was almost non-existing, by the way. I don't think there are much people around here knowing much about it.