Had some success with backgrounds, trial and error really. I have no idea how I got it cracked, but it works.

Here is the result in some pictures.

First is the background image loaded with the default Poser settings.

The next one, I guess that the image is sort of wide screen shaped, so I stretched it two and a half times in the U_Scale settings.

After watching the image disappear from left to right on the screen, I decided to give it a minus coordinate and there it was 'all correct'.

Didn't mess with after that, so there maybe there are more options with minus coordinates.

Hope it helps.

Pat :)