ActionScript 3.0 :: ArrayCollection As Tree Data Provider

I have been trying to populate a tree control via an httpservice that uses php to talk to a database. The queries work fine and the data comes back in the following format from php:
echo "<root>";
echo "<topic>";
echo "<sectioncode>$sectioncode</sectioncode>";
echo "<children>";
echo "<labtitle>$title</labtitle>";
echo "</children>";
echo "</lab>";
echo "</root>";

Flex can see this and interprets the heirarchy fine unless i try to format the resultformat in the httpservce (if i do that it goes a little nuts). The results from the php query to the db come back as an ArrayCollection with each containing a "root->topic->sectioncode->title" type of structure (which is what I want). When I go and try to use this Arraycollection as a dataprovider for a tree control, it doesn't work at all. When I use the arraycollection as the dataprovider I get [object,object] for every row in the tree and there is no parent/child structure.

Ideally I would like the title to be a child of the numbercode, but when i try and format the return from xml like that the number becomes and object without a value and the title becomes a child. I have a feeling that I am missing something in the php return to show the structure to flex more clearly and also something in the tree to implement it as the data provider better. Here is the code that I am using in the tree:
<mx:Tree x="25" y="48" height="451" id="ilabtree" dataProvider="{labarray}" labelField="@title" width="152" textAlign="center"></mx:Tree>