I am wall mounting my Bravia 49XD8305. The power cord from the PSU brick to the TV is captive and too short. I need an extension cable which fits the 19.5V side of the supply.

I don't want to extend the figure 8 cable and mount the PSU brick behind the TV, I want a solution that extends the 19.5V side of the power supply whilst still ensuring that the warranty is maintained.