Here is my problem:
I got one mesh in maya.
The uvs are spread through 2 uv cadrans.
I export as obj to zbrush.
Import it in zbrush, add some subdivision with some details.
Hit polygon uvs groups, ctrl+shift click a region, hit zmapper.
Then when I create the map zmapper goes crazy and make a non-sense maps. (I can use different config it won’t change anything)
My god if anyone of you can help me I would be more than grateful I searched so much on the forums!
Do you mean UV Groups or UV Sets?
OBJ not support multiple UV set.
Here are the my uvs in maya 8.5: 
I’ve been searching the forums for a whole day about this issue…
I don’t care if the uvs are on top of each other I just want a workflow that I can work the texture / model correctly and export normals/displacement and texture map without having to become mad… I can believe how complicated this turns out to be…
As noted here,
http://www.zbrushcentral.com/zbc/showthread.php?t=50984&highlight=zmapper+group
ZMapper 3 no longer works with multiple UV groups; you have to split them into seperate meshes
Tool>Polygroups>Uv Groups then Tool>SubTool>GrpSplit before generating normal maps, or you end up with garbage maps.
No, I’ve no idea why something that was working in Z2 is now broken either.
It’s working! Thank you soooooo much.
But does this technique makes good seams?
I dunno whether the mesh split causes seam issues; usually whenever I’ve had issues with really obvious seams (and to a certain extent, seams are unavoidadable) it was more to do with my UV layout and original geometry than anything else.
You do have all of ZMapper’s various seam controls, and looking at your UV layout the pieces seem pretty close together, so you may want to play around with the Seam Overpaint settings.
to fix seams i will (for a torso for example) i make sure that the areas that will have a seam dont overlap. so i cut the top uvs and move them to 0-1 space with the bottom piece delete all but a few rows of polys above and below the seams then use the zmapper capture and progect normal map feature to generate the normals i use to comp in photoshop to cover the seam.
you may try also to apply the normalmap to the model as a texture in zb and use the fix seam option under the tool texture menu. i try to shoot for at least a 25 pixel bleed
mm
monkeymuscle: I doubt we can use the fix seam option since the mesh as 2 textures for itself and zbrush cannot display both at the same time.
For the other method I didn’t understand 