I have tried a bit more with "Universal Radio Hacker". And now I think I found the right configuration to decode the signal. I read that 600 is a typical baudrate for FSK. So I configured the URH interpretation module to this value (Samples/Symbol) and here we are!
Window sensor 1:
Window sensor 2:
The signal from sensor 1 is decoded to 349B.4934.926D.3492.49A.
The signal from sensor 2 is decoded to 26D2.6BB4.9269.B492.49A.
The next step is to modify the SignalDuino firmware for the nanoCUL, to receive the same signal.