Not sure the 3d modeling program you are using, but I just used
FragMOTION to test creating multiple meshes and it was easy.
I opened an animated FPSC model and it had 1 mesh.
The I duplicated the mesh to create a second one (could have been any created mesh though but duplicating was easy)
Then I created a new bone that was not attached to the old ones.
Then I assigned the new mesh to the new bone and exported as an X file.
Loaded it in AppGameKit and did a GetObjectNumMeshes( objID ) and it returned 2 for the number of meshes.
It goes back to that other thread about meshes today, it is all about the bones and their assignments.
If you have multiple bone sets, then you will have multiple meshes as long as they have been assigned to the bones.
EDIT
I guess I may be wrong about the bones after all.
I just tried again and opened another character from FPSC.
This time I just duplicated the meshes group of vertices/faces then exported the X file with out adding any more bones or assigning the new mesh to a bone.
Loaded it in AppGameKit and did the GetObjectNumMeshes( objID ) and it returned 2 for the number of meshes.
So, it seems FragMOTION has no problem creating models with multiple meshes for AppGameKit objects.
EDIT
Okay, this is strange, because I tried it again from scratch.
This time I created a couple meshes, then bones, then assigned them, and exported.
It seems that when I create a model from scratch, it only recognizes 1 mesh even when I duplicate like before.
Yet, adding to a loaded model then adding and exporting it recognizes it.
So, there is something in the schema that is different, and I bet it is something simple we are overlooking.
I'll keep trying to figure it out until someone comes in and tells us what we are doing wrong.
Coding things my way since 1981 -- Currently using AppGameKit V2 Tier 1