This is the Launchpad action that you want:
Code:
## Launch the Kindle Web browser from the Experimental page.
B = #'k3_Home' 'Menu' 'k3_FW_Down' 'k3_FW_Down' 'k3_FW_Down' 'k3_FW_Down' 'k3_FW_Down' 'k3_FW_Down' 'k3_FW_Down' 'k3_FW_Press' 'k3_FW_Up' 'k3_FW_Press'
Then, you simply press Shift-B to launch the browser from the home screen.
I've also attached an INI file than you can unzip and drop into the "launchpad" folder on your Kindle.
Don't forget to do Shift-Shift-Space after you've added this action and ejected the Kindle from your computer.