Attached Link: The Clothing Designer Suite

So by transgender clothing you mean non-traditional male to feminine clothing for men? Interesting... I'm curious to see what you come up with.

Drawing directly on top of a 3d render works pretty good, imho. If you're not trying to make 3d clothing, this may be the most straightforward and fastest way to go.

Another alternative to the Virtual Fashion program is PhilC's Clothing Designer bundle:
http://www.philc.net/BasicClothing_page1.htm

M4 support was just added, it's a free download.
http://www.philc.net/BasicClothing_page3.htm

PhilC's Clothing Designer works better inside Poser than Virtual Fashion, while Virtual Fashion is great for making images outside of Poser (I think).  PhilC's Clothing Designer can create Dynamic Cloth (like Virtual Fashion) or Conforming Clothing.