Writing a rule to match a header name and value

[Geoff Soper]

I'm trying to write a rule that matches both the name of a header and its 
value. I've had no luck so far, can somebody point out my mistake?

My current attempt is:
header          __GS_PHP_ORIG   ALL =~ /^X-PHP-Originating-Script: [0
-9]+:(Mailer|Sendmail|Api).php/i

An example line is: 
X-PHP-Originating-Script: 20039:Api.php

Thanks,
Geoff