I've developed a working application for 3rd edition. I've successfully executed it in emulator. It uses capabilities for accessing the internet (WebService) for example.
Then I install the .sis package (signed of course) and try to run it on device. Installation only informs me that I've used a developer certificate for signing as it should. My application only blinks for a second and then dissappears with no error/info/warning/panic message of any kind. I've tried all kinds of tricks including displaying info messages (none of them show up), different UID3, yelling to it, executing my application while standing in one leg and barking like a dog etc.
Oh, I'm using 3rd edition MR version of the SDK, WSDL->C++ tool (yes I have installed the XML Data Binding package to my device) and Visual Studio with Carbide.vs for developing.