Theres no need to, music plays through transmitter and Sygic mutes it automatically when there is a turn or whatever....

I dont think you can set the transmitter on permanently as far as i know it times out after a short while of not sending anything. I remember reading a workaround someone was using on here of playing a 'blank' music file on a loop, 'tricking' the transmitter into staying on. Would probably work? although surely that means you cant have any music in your car??