In the Wave editor (Generators>Fourier) as well as in the Oscillator (when MaxMI = Double pi * 2 and Modulation is set to Frequency), the phase range from 0 to 1 corresponds to a range in radians from 0 to 2π (which corresponds to 0 to 360 degrees). The phase is linear so to convert from degrees to the (0,1) value, divide your desired value in degrees by 360.