PHP5-SOAP Questions

Hello... I'm trying to decide whether to try the PEAR::SOAP or the native PHP5 SOAP extension. I'm going to be working on a project to upload product data to Amazon's Seller Central. This is an area for merchants who are selling products via Amazon. Amazon has API's and reference documentation for .NET and Apache Axis... however, I'd like to use PHP if I can. I need to be able to use the WSDL's Amazon has available. I also need to be able to send attachments via DIME or MIME encoding and also use the HTTPS protocol. I can't find much documentation about the PHP5 SOAP extension, such as how to go about attaching a file. Essentially, I need to send my clients product database to Amazon at predefined intervals via SOAP. I lean towards the newer PHP5 extension, but I need to be able to attach files to the SOAP request. Can this be done? Does anyone have any experience with this or code examples? Thanks, - BR