Using helpers in Routes.php ??

[eluser]umbungo[/eluser]
I would like to know how i can use a helper in routes.php.

I have a list of main categories in config.php, and a custom url helper. I would like to do the following instead of mainting 2 separate lists;

Code:

foreach(config_item('categories') as $category){
    $categ = url_encode($category);
    $route[$categ] = "main/main/$categ";
    $route[$categ.'/:any'] = "main/main/$categ/$1";
}

However this stops everything from working. I tried loading the helper manually also (it is in autoload), but this didn't help.