I see a single edge line splitting in a double edgeline.
Is that what you are talking about?
Because a split  in that area is never a good idea.

Earl, in Blender, in uvmap editor, select the front and back short UV map.

Then go to => UV => Minimise strech.
That evens out what you have now.

You have edges close thogether, and edges far apart, this option evens that out and should help you on the way.

Secondary advantage is that you get a far more even texture distribution ver your object file.

Do not do this everywhere!!!!!!!!!
Sometimes you want this, sometimes not .

Just curious : Why would you want to make Mat Pose files?
Have you seen this?
http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2882166

Now next question :

Where is the manual on how to get this to work in Poser?

Poser does not eat nor drink : daf, def, dif, dof, duf, files.

If DS or DSON are required during the process?

The "Del" button is armed and ready.

Ha, stranger it gets. LOL.

I was logged in, I had to log out !

Then I could add V6 to the cart, and then log in again during the checkout.

Did you clean out the Deleted Items section?
It is something I forget from time to time, to remove the deleted onces.

Even with an emty cart, I always get the error Maximum 1 allowed.

The next steps where a textbook example of how to make something very simple extremely complicated.

No clue as to what they are releasing, but the fingers are way too thin.

Retopo is only partially usable for Poser.

What do you do with opening - closing mouth? Eyelids?
What about inner mouth? Teeth? Eyeballs?

Retopo is a new mesh in need of a uvmap.

JCM's and other exotic old school hacks are not an issue. Learn how to paint a Weight- and Bulge map, and they are a thing from the past.

But? And here come the catch !
How are you gonna safe the obj file? => This is a deep question for insiders.
Build the groups in Poser? => Same deep question for the same insiders.