Hi Claymore, I haven't examined the model, but a way to overcome this "collision limit" would be to create a new part and link it to the wing part (or the fuselage) that needs some collision added.
Let's call this new part created "WingAuxiliary_D0", for instance.
It would be made of only one face, a small triangle, with Gloss or matt material applied, it doesn't matter wich one as it would be non visible from exterior, anyway. Also, "separable" flag will be omitted for this part.
The pivot point can be the same as the part that it will be linked to.
So now you can add to this new part up to seven more collision boxes, and they can be external or internal or a mix of them. And not necesarily they have to be INSIDE this part, they can be related to some other part that already have all "slots" for collision filled.
It may be necessary to make some adjustment in the Java code to reflect parts name changes, in the Hit and Cut methods, to tie everything.
There are many other examples, but check for instance, the B-25 model to see how that it's already done in the game.(look for an Auxiliar_D0 mesh or something similar)
Anyway, the idea behind is, if you need more than 7 collision bodies, make a "dummy", non visible from exterior part, link it to the existing hierarchy and add the extra needed collisions to it. Revise your code to make it work properly.
EDIT: sorry, I corrected the post, the new part created doesn't have to have the flag "hidden", it only needs to be hidden inside another part. I mean it should'nt be noticeable from exterior view (its only a small tringle, so not difficult), its only purpose is to serve as a container to have more collision bodies. If it has the flag "hidden" the collision bodies will be deactivated, so it won't work as intended. Sorry for the mess... I was a bit in a hurry
PD. Maurice, I missed you...