LTspice FFT Result Visualization Difficulty

Hi,

   I am using LTspice on the circuit EMI spectrum study. Let's say I have two waveforms for V1 and V2. I wonder if in LTspice, I can plot the FFT results for : 

   (1) V1+V2

   (2) FFT(V1) and FFT(V2) on the same figure

  I tried but it does not seem LTspice support these functions. Could anyone help me with LTspice? Thanks for help!