Hi,
my EOS 06 with RCD 300 has no AUX-IN. I read on ebay an auction stating that it's possible for a Volkswagen centre to activate the AUX function of the RCD 300 using VAS. If this is done (the user can then enable AUX by pressing the CD button a couple of times) it's possible to plug a 20 euro cable that doesn't need an interface.
What do you think?