Specify UV Map for Lightmap Pack

Right now for the Lightmap Pack there is the New UV Map option.

It would be so much better that instead of that option there is a option to specify the name of the UV Map and create it if it does not exist.

It would make updating a Lightmap that is shared with a lot of objects a breeze. Where as of now it's a painfull process. It also seems this would be easy to implement.