Deap Space objects including the Milky Way in general are pretty low contrast objects. So filters seem to be a good idea if one can be found to pass the correct parts of teh spectrum. It appears that a Kodak 3x3" (75mm) #32 Magenta Special Color Effect Wratten Gel Filter
will do the trick. According to various sources I found it will pass 320-500nm and 600nm plus thus removing much of the green parts of the spectrum. The green range includes a lot of light polution and sky glow from O2 in the high atmosphere. This should bring out milky way nebulosity and structure though it may reduce stars a bit.
I need to figure out what the best way to attach one of these to the camera is, but I expect its not too complex.