How to modify XML on Objective-C?

I'm working on a project for the iPad, I need to read and write to an xml file, which is also used by the counter part of the application in windows.

The problem that I have is that I've been looking around but I haven't found a way to modify an element or att开发者_如何学Pythonribute in an xml, without having to build the whole xml again.

I saw this other post, which is basically the same problem that I have, and I also end it up in the same point as the person asking the question, NSXMLParser and TouchXML are read only and do not allowed me to modify my xml.

Any other suggestion about what can I use?

Thanks!