Automatic message display on T29G

[yc12843]

We have a simple Asterisk-based IVR that answers the phone for our company and allows the caller to choose an extension to ring.
The secretary at the reception desk has a T29G with a EXP20.
I'd like to be able to use the phone's display to show the Caller ID info of the people who dial into the IVR, without ringing her phone;
(she's not supposed to answer it unless they dial her extension, or 0).

I thought of doing it by having the server send her phone a SMS containing that info.
So, is it possible to automatically display incoming text messages (SIP MESSAGE) in an unobtrusive way?

Such that:

• Text is shown automatically, no need to push a "view" button.
• Doesn't disturb current calls, if any.
• Doesn't cover (all) the dsskeys' text labels. (it's fine if some are)
• Automatically go away after a delay, unless it's very unobstrusive.
• Doesn't prevent dialing and other functions if the user ignores it.
  

So it'd be acceptable if they'd be shown as part of the background wallpaper or something.

If that's not possible, is there another way it could work?
Like, dynamically changing a dsskey's label would work too if that was possible (?)