as MS does not change it, the Remote Desktop Mobile application still disconnects a session after 10 minutes idle time.
Although there is a solution for Windows Mobile 6.1 (http://www.hjgode.de/wp/2009/09/18/wm6-1-remote-desktop-client-disconnects-after-10-minutes/) based on the posting of Rafael (MS Support), this will not work with Windows Embedded Handheld (WM6.5).
The TSSHELLWND will not react on mouse_event and you have to replace the calls by SendMessage and send the WM_MOUSEMOVE to the Terminal Server Input window.
The attached application will do so but it will start only on Int*rm*c devices. It sends a mouse_move message all 4 minutes to the TS input window and so the idle timer will not timeout.
If you ever need to stop RDMKeepbusy from running in the background, you will need StopKeepBusy which is part of the executable download.
For visual control, RDMKeepbusy shows a small blinking line in the task bar:
green = Remote Desktop window found and input window is active
yellow = Remote Desktop window found, but no input window active
red = Remote Desktop window not found
Version 1: REMOVED as nobody seems to use the actual version
Version 3: REMOVED as nobody seems to use the actual version
Version dec 2011: REMOVED as nobody seems to use the actual version
Latest version always at GITHUB (WM 6.5)