TYK,
Sorry for the delay in getting back to you. I had to investigate things a little further. Unfortunately, it looks like that's a change in how Facebook displays the Like Box now. When you originally posted, I looked at your code, which was a little old. Now, your site is using the newer way of including the box, which is good.
Also, originally, I tested the 'dark' colorscheme in Facebook's Like-Box creation tool:
developers.facebook.com/docs/plugins/like-box-for-pages/
If you change the Color Scheme to 'dark' in the settings area, you'll see what I think you're looking for. However, once you check the "Show Posts" box, the stream will display. It seems like the stream will *always* have a white background, regardless of the scheme setting you've chosen. That is a change from how the Like Box used to work, but unfortunately, there isn't a way to override the behavior.
With that said, in the next release of JFBConnect, v6.1, we'll have a customizable social stream widget that you will be able to fetch the posts from your Facebook Page (or FB Group, Twitter Stream or LinkedIn Company Page) and show them however you want within your site. CSS will fully work and you'll be able to include/hide different settings.
The 6.1 release will be out around the end of this month.
I'm sorry for the confusion, and I hope the above helps explain. If you have any other questions, just let me know.
Thanks,
Alex