I made once a ac generator which was capable for automatic syncronising with an external signal for 45 till 65 Hz (zero crossing) and it had an output from 0 to 230V sinewave (input 0-10V). I used a pic16F873 on 20Mhz. So it is possible. I cannot give you the source because I made some promissis about the it for not given the design away. I say it is possible, just try !