Loss of functionality when playing IPOD Nano through Car

I have been using my IPOD Classic in my Mercedes via the Aux cable provided with great success and enjoying its full functionallity through the vehicle Comand System.

Have now bought latest Nano and this has a narrow imput so have borrowed a friends adaptor that reduces the wide input to narrow. Whilst now able to play selected Albums and tracks this appears to be in permanent shuffle mode. Have bought a new Aux cable with sterio jack but again same problem.

Any suggestions would be really appreciated.