Iphone 5 charging issues

[Albert Trousers]

Just got the iphone 5s, upgraded from iphone 4.
I have in the car a unit that plugs into the back of the stereo & into the iphone 4 which the charges it & allows me to play music through the source button on my stereo.
Iphone is a different charge fitting so I bought a connector that plugs into the in car charger & then into the iphone 5 but i get the message "this cable or accssory is not certified & may not work reliably with this iphone"
Does anyone know a way around this?

Ta

[keyser_soze]

I think they recognise non-Apple cables and connectors these days.

[DaveDRFC]

Some of the 30 pin to 8 pin adapters don't work with audio, there are loads available that do though if you are having bother. The official Apple one is about £25 but can pick up a third party one that will do the same job for 3 or 4 quid off Amazon. Just check the reviews to make sure it will do the audio as well rather than just charge it.