Tanveer -
First, let me say that Hugo knows more about this than I do.
That said, there are a few of us working on the issue. When we are done, and we are hoping it will be very soon, we're going to publish a tutorial on:
http://www.bloggertipsandtricks.com/In case you aren't aware of it, BTT is an extremely good resource for Google bloggers.
It's not that hard to integrate Nabble with Blogger, but we are working on a solution that we hope will be best for optimization.
With Hugo's permission we will publish a link here to the tutorial.
HTTPS Please!