Screensaver application on Windows CE (5.0 version)

[stephzz]

Hello all,
I am developing a screen saver application on Windows CE 5.0, using Visual C++ and Windows API.
Has anyone here worked on such application, could you please share me your experiences? It is not easy as what I thought at first.
As what I know, Windows CE (and Pocket PC) does not support Screen saver like Desktop. In Desktop, developing a Screen saver is easy, windows API supports DefScreenSaverProc function, we just develop screen saver as .exe and just rename it to .scr
But in WinCE, we cannot do like that. WinCE does not support Screen saver, so there is no DefScreenSaverProc function, and if we rename .exe file into .scr the OS does not execute the file.
So we have to do everything by ourself.
My idea is: To start screen saver, we have a background application (a service or no-window application) which will "listen to" the system, after a predefined time (for example, 5 minutes) if there is no action on machine (no tap on screen, no press on machine's keys...) the background application will start showing the Presentation of Screen saver.
To implement this, I think about Hook technology, but as what I researched until now, Windows CE also does not support SetWindowsHookEx function.
Now I'm getting stuck.
So, if anyone has deals with an application like mine, could you help give me some ideas? How did you solve this problem? How to activate the Screen saver in Windows CE? Which technologies do you think that can achieve this?
Your responses would be kindly appreciated.
Thanks.