IPhone 5 adapter and speakers?

Okay, so I have ordered my iphone 5! Yay! But i already have two speakers i charge my phone with and play music through. (one logitech and one yamaha) I have looked on ebay for a converter, they are all cheap but they all say they don't support audio and video. I'm not too phased about it not playing video but does this mean even if i plug the adapter into my speakers and then my phone the music won't play through? Someone who actually knows the answer can you please help! 10 points!

If it says that it doesn't support audio and video, then I'd bet on the safe side and assume that you won't be able to play any music.
I tried a quick search without luck either! (On ebay)
On Apple's website the adapter does specifically mention the capability to do audio, but no video.
I've included the link to the adapter in the "sources".