Help with OS X mod rewrite rule

Mod_rewrite not working on OS X

[triso]

I need some help with this rule. It works fine on Linux, but I have just started working on OS X and it refuses to work. I have to use [R] to make it work, and this defeats the purpose of the rule.

I want domain.com/category/product.html to be equivelant to domain.com/index.php?x=category&y=product

This is the .conf file I am using (note the [R] which gives the wrong result as it redirects to index.php?x=..., but will not work at all without it)

<IfModule mod_rewrite.c>
  RewriteEngine On
  RewriteRule ^/([A-Za-z-]+)/([A-Za-z-]+).html$ index.php?x=$1&y=$2 [R]
  RewriteRule ^/([A-Za-z-]+).html$ index.php?x=$1 [R]
 </IfModule>

Any help with this would be greatly appreciated.