[SunHELP] ksh & PS1

under ksh, the below example will update the pwd as it changes but not the
user if I su to user.  This is understood
that if I used the '-' switch that it would run there profile and thus the
same prompt would have to be in place
in users profile.  I could set a $USER variable within each profile but I
want to check if I'm reinventing the
wheel first.  Interested in anyones solutions and thanks for comments.

export PS1='('`whoami`'@'`uname -n`')$PWD-> '