Adding/Removing programs to your desktop
Historical purposes only this part: UME keeps the .desktop files in /usr/share/mobile-basic-flash/applications, so you can either create a new .desktop file for your app, or make a symlink from your app's .desktop file in /usr/share/applications
UPDATED INFO
Put your desktop file in /usr/share/applications (or subdirectories thereof). Also add
OnlyShowIn=GNOME;Mobile;
to the desktop file and the icon will appear on the desktop.
Also something to note:
For example, cheese does not have OnlyShowIn but it appears in hildon desktop...others also do not have OnlyShowIn but do not appear..it seems that there is some special implementation for ubuntu mobile which is seen in the gconf keys:
/desktop/hildon/htmlhomeplugin/onlyshowin_filter
Check OnlyShowIn value in .desktop. If _False_ then every .desktop is shown.
and
/onlyshowin_ignore
Always show these apps, even if they don't have OnlyShowIn. Cheese is in this list hence it is always shown
Apparently this key should go away when every application is a good citizen and complies to the freedesktop.org standards.