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How to control how close UV Master crops the edges of the UV map to the UV islands

I am using the UV Master plug in to create UV’s of a dress mesh. I have it divided into two polygroups one for the front and one for the back. When I unwrap and then flatten to view the UV map, I see that one of the UV islands is always right on the border of the UV map it self.

I want to create some space between the UV islands and the edges of the UV map.
How can this be done? If I scale the UV islands in the flattened state in UV Master to set up the spacing the want I want, Zbrush always reverts to this really close cropping?

The pic below is an image of the texture map that is just white, but you can see how closely it gets cropped. How can I get Zbrush to crop this differently?
I am assuming that for the map to work correctly the islands have to stay in the same place that zbrush put them meaning I cant change the cropping in a 2d editor?


Thanks