I commented, I sculpt in zbrush 4 displacement maps for my M4 and V4, then export (multimapsexporter) them and use them in poser 2012 .

what I'm looking is load my model (v4 or m4) in zbrush with UV (that's no problem) and then apply existing displacement maps to the model in ZB for the purpose of  continue sculpting or modify the original displace map , no starting from 0 but rather from those already made

I tell you that I could do in this 3dcoat (vercion trial ) and I read that in photoshop cs5 extended vercion also be done but  the problem is  I have Zbrush4

This is something you can do, however, if the UV's overlap, it may cause some unwanted displacement. You may need to break the object up by material.

To get an external displacement in ZBrush, load the image into the Alpha Channel. Then go to the Displacment Submenu of the Tools menu.   Select the image in the Displacement map window and make sure you have MODE turned on (this should auto turn on the Disp On button but if not, turn that on).  Then adjust the intensity to taste and hit APPLY DISP MAP.  You'll also need to have a texture active if you want the displacement to be viewable.

Hope that helped.

If you're unsure about what a button does in ZBrush, just hold the CTRL key (I think it's the CMD key on a mac) and hover your mouse over the button. A description will appear.

This Wiki instruction should be a clearer step-by-step :

http://www.pixologic.com/docs/index.php/Applying_Displacement_Maps

Quote -
This Wiki instruction should be a clearer step-by-step :

 Http://www.pixologic.com/docs/index.php/Applying_Displacement_Maps

MMM, looks interesting, can be a solution .... , may need to be investigate and apply various maps to an object as it does not respect originals uv

I will investigate a couple of ideas I occurring , but it is a very very good starting point, thank you very much for reply teyron , I reporting If I get succeed results

UV's in ZBrush are flipped along the V axis.  Keep that in mind. You can flip textures in the Texture menu.

Quote - UV's in ZBrush are flipped along the V axis.  Keep that in mind. You can flip textures in the Texture menu.

I had completely forgotten about that, now I see why my tests were a complete failure, thanks for the warning , I will try again