Quote - Thanks, I don't know how to create a transmap, I am new to this Poser stuff and I think Poserworld requires membership.

Here is a tutorial on how to make a transmap.

http://www.reddragongraphics.co.uk/1.html

Basically: 

the colour black hides everything making anything it is covering like it's not there

the colour white reveals everything making anything it is covering competely visible

various shades of grey give  a "see through" appearance to whatever it is covering. The amount of "see throughness" depends on the shade of grey. Darker greys are more see through. Lighter greys are less see through)

In the case of the dress, you would make the top part of the transmap black and the skirt part white.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi