Hi,
For the moment without a TMAP editor, I have tried one technical, temporary solution.
Rework entire diffuse texture to 512 and repeat this to entire canvas.
For ex. Here the original 1024x1024
Resize image to 512x512
Expand canvas to 1024x1024
Rework your texture with your material and make a flatten image
I have made this
And after a new Alpha Channel
Now import this material in your 3D Software and make a set UVs map without Overlapping.
When you have ended the work, Bake the Occlusion Map.
Attention, without Overlapping! Only the objects that are equal can be with Overlap. For ex. the safeboat in a unit is ten. Bake only one, because all the safeboat is in the same place on the texture and UVs coordinated.
(In this example the the texture and Occlusion is not complet)
Open the Diffuse texture, apply the Occlusion in a new layer
Continue
BEST REGARDS
UBOAT234