Sorry, just saw your message, I don't check my profile too often, haha. One thing I can't really figure out is what you mean by using an external flash to get the seemless background. Right now I am just using a DIY lightbox made of a cardboard box with squares cut out and covered with thin tracing paper and a 10MP digital camera. I do plan to upgrade to a DSLR some day but I just haven't gotten that far yet.
Over in the Lets see some cool stuff thread you asked Gogglev how his backgrounds and foregrounds look like one solid piece. I use the same kind of set up and got a lot of input from him when I made it.
There's a sheet of black paper or cloth in the background and the figure stands on a plate of glass (spray painted black on the bottom). The trick is that we don't use continuous lamps but an external flash and edit the photos to get a rich, seemless background.
I'm not sure what kind of camera/set up you're using but if you have any questions, feel free to ask.