[kapitan_zur_see]

Though not a professionnal by any means, i quite know my way around 3dsmax and 3D in general. From what i've read here, you got everything correct Skwas.
The problem we indeed face off while using pack3d is that it can only import one texture channel, which is the diffuse one, alongside only ONE uvw texture coordinate (that's particular to .obj format), hence, occlusion map is bypassed and will be confused while ingame.

For people that are interesting in what occlusion mapping is, it is generally used in the gaming industry and more or so, you made them by using "rendering to texture" function in 3DSmax which is also called "baking texture". It is basically generating a texture containing information on how to render lighting for a rendering engine. The main purpose of occlusion techniques are to mimic the quality of a raytracing or radiosity rendering. Those two are very professionnal rendering method and while they produce very high quality images (they use it for instance in those pixar movies and the like) and precise depicting of real lightning behaviour, they are very processor hungry and therefore, cannot be use for the gaming industry as it is not precalculated animation, but requires of course real time rendering. Not that it couldn't, but you would just end up with something like one frame per MINUTE.

To sum it up for the occlusion lightmap (there are other occlusion type of maps by the way), Typically, 3dsmax will first do a raytrace rendering with complex light sources algorythms ( don't know of...lol) for a high quality depicting of shadows and light behaviour and will then "project it" on a texture. This is why it is called baking texture or "rendering to texture". Another kind of those rendering to texture techniques, is the well known normal map wich is also precalculated into a 3D program in a quite similar way.

As It is with pack3d now, the lack of occlusion channel will produce flickering and stuff typical to bad uvw mapping and the like. That is, unless you create a 3d object specifically "made" in the dat file to be rendered SH3 way (you can actually "clone" a SH3 object like one u-boat and overwrite one US sub or whatever with it and bang, no texture flickering but looks out of place due to rendering engine improvements between SH3 and 4 and therefore, is certainly not a solution to be considered).

Well, i hope i didn't sound all too confusing and "academic" lol