Timestamp in AIX Prompt

I am using ksh under IBM's AIX, version 6.1.
I wopuld like to add the current time to my prompt. I understand that I can change the value of $PS1 in my .profile. So far my attempts at setting the time have resulted in setting the time to what it was when the .profile was executed. ( It doesn't advance as time moves on ). Any ideas ?

export PS1="[`date +%T`] "

But, I am not sure how to refresh the time.

I don't think this is possible unless you have ksh95.

If you do ...

http://www.unix.com/shell-programming-scripting/23397-help-setting-ps1-prompt-include-current-time.html