Infrared Control of Car Stereo?

After a bit of a hiatus I'm back and eager to get started/finished with some projects for my car.
When I learned that the PICAXE has IR capability I envisioned building a small 4 button remote to control my car stereo. Like how hard could that be right? Well, it's turning out to be more complicated than I hoped. I've searched around but I can't find anything that lists the codes/protocols for my Pioneer receiver. I know there are IR decoders that a person can buy/build, but I don't want to get that involved.

I know, IR coding is probably a subject that's been beaten to death on this forum. I searched but I couldn't find anything helpful on this forum or any place else. Can anyone point me in the right direction? Thanks!

There are three possible paths to follow here.

1. If you have a working remote already, then use a decoder to 'read' or copy the codes from it to replicate the remote. Se note, below.
2. If you know the model of the remote, go to the LIRC site (Linux IR Control) http://lirc.sourceforge.net/remotes/pioneer/ to get the codes.
3. Get a universal remote that can interwork with your stereo.

Note: I posted a PICAXE decoder for the NEC IR format, which is the most common protocol used by equipment manufacturers. I had a quick look on the LIRC link that I provided above and Pioneer seems to conform to the NEC format.

Thanks for the info. I guess I have some studying to do. Ugh.
Here's a 4th option: I did a quick search on eBay and found my remote for less than $8 shipped. I could buy this and hack it up, but where's the fun in that? I'd rather build something around a PICAXE instead.

Having an actual remote is really helpful in determining if the signals can be replicated by a PICAXE and doing that. It may well be worth the investment just for that.