Put the below in your ~/.emacs:

;; make thinkpad browser keys navigate buffers
(setq w32-pass-multimedia-buttons-to-system nil)
(global-set-key (kbd "") 'next-buffer)
(global-set-key (kbd "") 'previous-buffer)
(global-set-key [C-XF86Forward] 'next-multiframe-window)
(global-set-key [C-XF86Back] 'previous-multiframe-window)

On my x220 this allows the browser forward & back keys (above right & left cursor keys) to be used to switch buffer and combined with ctrl to switch frame / window.