Is there any way to change the "workstation locked" screen on the 4.91 spx

What we want to do is:
1) reimage the PC (zen imaging)
2) auto login
3) lock pc with a message on the "workstation lock" screen that shows why
it is locked
4) install updates like XP hot fixes and NW client fixes
5) shutdown or restart

Basically any way to show a message ON TOP of the "workstation lock"
screen or change the screen itself temporarly.