Well, I'm not quite sure. But why do you have to do that in the srm.conf?
Try configuring it all in the httpd.conf. Without ever touching the srm.conf, I still load up PHP files perfectly.
Have a glimps at this tutorial, this is what I used, the very first time I installed apache+php, it worked great from the begining:
http://hotwired.lycos.com/webmonkey/00/44/index4a.html?tw=programming
Hope I could help ya. 🙂
M