Seemingly this facility doesn't exist, or is not known about.
Never mind, I've now done it manually.
On similar subject how have you set up your WACOM tablet express keys/touchstrips etc for Lightroom 2?
I have the express keys on the left set to the defaults, as they come in handy in Photoshop. I have the left side strip set for zooming, and the right side strip set for the bracket keystrokes so that I can tap and increase or decrease brush size.