Retro Fit CD Changer

Just bought my first Merc 2 days ago, does anyone have any knowledge on retro fitting a CD autochanger into the Glove box of an 2005 E270, I can get the cables and brackets from Mercedes for around £20 which autochanger or changers are suitable for the glove box retro fit my head unit is the single CD Audio 20, how easy is this job and are there any diagrams anywhere for retro fitting?

Thanks Dale