Eclipse and Android: cannot debug on Samsung Galaxy S2 because not detected

I am just starting to learn on Android development. I use Ubuntu 11.10 and Eclipse. I have installed the needed plugins from android development, and I have also write yet some examples that compiles and run fine on the emulator. But somethings as multitouch cannot be tested on the emulator, so I want to test them on my real Samsung Galaxy S2 device. The problem is that I have tried everything I have found on the web on this, but still have not been able to use it. When I run ./adb devices, it does show none, although the device IS attached. ``` $ lsusb ... Bus 001 Device 012: ID 04e8:6860 Samsung Electronics Co., Ltd $ ./adb devices List of devices attached ``` I have modified /etc/udev/rules.d/51-android.rules many times in different ways following instructions on the web, but none of them make a difference. Currently I have this line in it: ``` SUBSYSTEM=="usb", ATTRS{idVendor}=="04e8", ATTRS{idProduct}="6860", MODE="0666", GROUP="plugdev" ``` Of course I tried restarting udev and adb services, even rebooting the whole system, but it did not work neither. Any hint? Thanks a lot in advance,