PHP Expat XML Parsing expert needed

We have a complex XML document that is a rendition of an EDI file for Medical Claims processing that I need to have a PHP script developed for Expat XML parsing on this file. Basically there are sections of the file that I need to get out into an array so that I can write them to a SQL database (Firebird). I can take over once I have a decent array of the data to work with, and we already have a Java app done that converts the EDI to XML, so we're starting with this XML file. I just need someone who is a bit of an expert in XML parsing to take this one task from me so I can pick it back up once I have a decent array to work with. If you feel this is a good fit for you, please give me some details of your actual XML parsing experience, particularly with large files, so I can review. I need this done immediately so please make sure you have available time to devote to this right away. Thanks