SVDL has a tutorial on how to create displacement maps in Poser using 2nd Skins. I've been trying, largely without success to replicate something simliar in Vue. The net effect is that he subtracts the base skin texture from the 2nd skin texture to create a displacement map. Works well in Poser, but does not work so well in Vue.
I'm hoping someone can point me in the right direction.
Here's what I've done so far:

1. I first tried to copy Svdl's method directly in Vue in a single layer to create my bump (displacement) map. Does not work as the displacement affects the entire texture, and not just the clothing areas.
2. Created a mixed material, using the base texture first, then the new displacement layer as a second layer with the same results as before. (Both textures showing displacement)
3. Same as 2. above, but created a distribution map using the same process as for the displacement map for the two materials. This had better results, but I am having trouble creating the distribution map in pure black and white.
   Several questions have arisen from playing with this:
   1.) how do you get displacement to affect only certain areas of the texture map? Nothing worse than seeing your figure suddenly swell up as if it were allergic to a bee sting.
   2.) How does one obtain true black and white from color images in the function editor? (I can get gray scale, but I need black and white.)
   I'm attempting to do this without having to create  other texture maps.

I would include images of my settings, but I'm on a Mac, and haven't learned how to do screen captures yet.

could you add a mesh texture in Photoshop of your skin and then make a pure white copy of it and use that for your displacement in Vue?

I'm attempting to do this without having to create  additional texture maps.
The end result is that I want to create a texture where a person can input their two texture maps (base texture, then texture with clothing on it (second skin)) and have instant displacement. Much like Silverblade's Dirt mat where one only has to input the texture they want to 'dirty'.
I think I'm on the right track using a distribution map, but can't get true black and white values from the end result of subtracting the two textures. Gray scale is all. And the slightest amount of gray in the distribution gives some pretty wild results...

can you not run it through one of the clip filters to force it to black and white ?

I've tried various combination of filters, but they tend to set different thresholds of where black and white should fall. This results in blank (leaving base texture) areas where cloth textures should be, and often leaves very noticeable artifact around the edges.
(wish I had screen capture on the Mac to show what I've done.)
Not being overly familair with all the filters and how they work, I've just been putting them in various ways and hoping for the best.

I don't have a MAC but just did a search and found this. 
The basic screen capture is the same for Panther and Leopard.

http://lifehacker.com/341135/leopards-additional-screen-capture-options

Thanks! Pictures will be forth coming today.

Well you can indeed use the SVDL method in Vue to create displaced second skins but you are not going to get results as good as using a specific grayscale displacement map.  Here are a couple of pointers however on how to replicate the SVDL method in Vue:

1.  In Poser, Black represents a displacement of zero whereas in Vue it represents a negative displacement.  Zero displacement in Vue (and most other graphic programs) is represented by middle gray.   So you will need to normalize the computed displacement map in Vue by using a "Map" filter to set all black values (-1) to zero (0).  Plug a map filter node into the computed displacement map and set the values as follows:

Input Range Lower : -1
Input Range Upper: +1
Output Range Lower: 0
Input Range Upper: +1

2.  In all likelihood, you are going to get displacement artifacts showing up using SVDL's subtraction method due to jpeg compression pixelation issues.  You can smooth some of this out by using a "Quantize" filter and then playing with the threshold and contrast settings. 

Thanks! I'll give it a try this afternoon!
And thanks for the tip about artifacts. I hadn't considered JPG compression to  be the culprit.

After numerous attempts, and using the recommendations by dBurdick, I find that the JPG compression artifacts are too difficult to overcome. In order to get a decent displacement in the render, the figure itself winds up having a very fine orange peel appearance. I get a better result using a standard bump map. So for now I'm going to table this experiment and perhaps I'll find a better solution in the future.