Try this thread: http://www.linux-hacker.net/cgi-bin/UltraBoard/UltraBoard.pl?Action=ShowPost&Board=3Com_Audrey&Post=649
Or just search the forum for "execv"
Basically, you install a small program called execv which executes a shell script as if it were a program. So you make a Browser.sh shell script, putting the commands to launch Voyager in it. Then make a symbolic link from "Browser" to /nto/bin/execv (or wherever you put it). Then, when the hardware button tries to execute "Browser", it executes execv instead, which causes Browser.sh to run, launching Voyager.
Internally, execv takes the name under which it was invoked (Browser, in this case), adds ".sh" to it, and executes the resulting shell script name. Nice hack by flipflop.
ACID and other Audrey apps