calling Unistaller from installer code

When my installer starts it checks wheather appln is already installed & if it is then it gives REPAIR & REINSTALL options on Custome page. If user selects Uninstall i skip all other pages & call uninstaller from already installed directory & quit the installer. Where should i write code for this?

In the custom pages' Leave function add WriteUninstaller, then Exec and then Quit.

-Stu

I just want to confirm that the uninstaller created by WriteUninstaller is created by using code written in Section Uninstall right?
where will be the uninstaller stores? can i change that path by SetOutPath?