ActionScript 3.0 :: Automatic Escaping And Stubborn Nodes?

What I'm trying to do here is to build a simple XML document and then submit it to a PHP script.I'm having 2 major problems:

1. Building the XML document. I'm not sure that I'm doing it right. If I don't first create a root node (mapXML = <xml/>; ) then it refuses to create any nodes. I would prefer to create "planet" as the root node, but if I do that instead then it just duplicates it (planet -> planet -> other child nodes....)

2. Even more annoying, it's escaping the quotation marks, no matter what I do. In the final XML document there are backslashes before the quotes.At this point I'm not really certain at what point it's happening, whether it's in the XML parsing or whether it happens when I prepare the data for uploading. I'm submitting a large Base-64 encoded chunk, though, so URLLoaderDataFormat.VARIABLES is out

Code:
mapXML = <xml/>;
mapXML.planet.@id = "1";
mapXML.planet.map.layer.@id = "0";[code]............

I decided I might want to compress the data before base-64 encoding it, since the map data is very large - 500x500 bytes. I tried deflate() with my ByteArray object. Didn't work. Said the method was undefined. Tried compress(). That worked. Why? The docs say it should be the other way around, that compress() only works in AIR. I am not compiling for AIR, and this .swf runs in the webbrowser just fine, compression and all)