Actionscript 2 saving data via XML and PHP

[kevansevans]

I have been googling the crap out of this, and I can not find the answer. I've been working on a flash game for quite some time now, and I want to incorporate an online saving ystem. I already understand that getting this to work involves XML and PHP. I already have a small script that displays a change log that I can update when I want, sort of acts as a place holder so things can stay organized. The swf in question is being hosted in my dropbox account, so servers have already been covered. I already know how to communicate between the AS files, XML files, and PHP files, but I can't seem to find any thing on how to save/write information that's been fed to the PHP/XML codes. How would I go about this?