I'm really interested in how to create a composite USB device. I mean a mouse and a keyboard emulation with Netduino.
Could you provide a sample please?
The UsbClient feature lets you turn your Netduino into a USB device (keyboard, mouse, joystick, or custom). Yes, you could probably turn your Netduino into a Mass Storage Device and access its SD card from a PC--although that may or may not require a little bit of native code as well.
Another nice feature of the Netduino's microcontroller is that it has 5 USB endpoints available. So you could make a "composite" (combination) device. A keyboard + mouse hybrid. Or a CDC serial port + Visual Studio debugging. Or get really creative...