Store a URL parameter into Apache log

On the first page of my site I'm passed in the url a UserID as in: [login to view URL] From this point forward the UserID is never passed in the URL and we cannot easily add it. However in the apache log we need the UserID associated with every line. We are running PHP through out the application so it is possible we could change enviornment vars or something if that is necessary. Ideas? Apache 1.3.28 or later PHP 4.3.4 or later (running as an apache module) RedHat Linux 8.x or later ## Deliverables 1) Complete and fully-functional idea with sample code as necessary. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Apache 1.3.28 or later PHP 4.3.4 or later (running as an apache module) RedHat Linux 8.x or later