Hi, it is possible through an external application. There's one included in Omnimo (WP7\Common\OmnimoApp.exe) or if you don't have Omnimo you can download just the app from here:
[link]It can be used like this:
LeftMouseUpAction=!Execute ["OmnimoApp.exe" ToggleIcons]
or if you specifically want to hide/show
LeftMouseUpAction=!Execute ["OmnimoApp.exe" Hide/Show]