First, follow the instructions on my prior link here:
Once you’ve done the above, you can post to WordPress blog and it will echo out to both Facebook and Twitter.
Next, manually connect Twitter to your Buzz. Here’s how:
Log in to Gmail. When you click “Buzz” and then click “Connected Sites”, you’ll see the source manager; this lets you control permission levels for each source (in other words, you can set it so that your posts via Twitter are shared with certain people as opposed to your default privacy settings). [Note: controlling this was pretty un-intuitive. You’d think you could get to this under “Settings”, but you can’t. Bad design.]
That’s it! Enjoy.