Modificaion of htaccess for changing how php and directori..

I have a PHP script that allows you to pass variables as directorynames

i.e. instead of: http://www.abc.com/test.php?id=12&product=34
I could write: http://www.abc.com/test.php/12/34/

Looking at the code I'm pretty sure it'll work, and I can parse all of the
data myself.

Trouble is my ISPs web server is interpreting the URL wrong and so test.php
is not being called.

I thinkt is treating the url as a folder '34' in a folder '12' in a folder
'test.php'
instead of test.php with a random string afterwards.

I get the error (500) "There was an error in the script
http://www.abc.com/test.php/12/34 or the script was not found."

Is there anyway to modify my .htaccess to say "if any URI in this folder
contains test.php simply call test.php and don't treat anything after as a
folder.

I can therefore use $REQUEST_URI to parse my URLs

Any ideas?

Cheers