How to log calls to webservice via SOAP in PHP

Question

Hi I am using a third party webservice via SOAP from a HTML page: http://www.monirulislam.com/test/gmap/HMap_GMapV2.html

This page refers to a proxy page (in PHP): monirulislam.com/test/gmap/HeatMapGenerateProxy.php

Now I need to know what parameters are being passed by the PHP file, what the webservice is returning etc. i.e. log all communication between my application and the webservice.

Will some one please describe what I need to do to achieve this.

You may have already guessed I am a novice in the realm of webservices and PHP and I am in the process of learning by implementing test projects. So some amount of detail/code will be very much appreciated.

Thanks in advance for your help.