Cannot add_filter for plugins_url function

Hi,

Today I would like to try AnsPress on my WordPress website I’ve already working filter like this :

add_filter(‘plugins_url’, ‘correct_form_url’);
function correct_form_url($url) {

… my stuff

}

But it doesn’t work only for Anspress plugins. After some investigations i found the problem. On WordPress plugins are loaded earler than my theme/functions.php so my filter is loaded after AnsPress initialization. AnsPress use “plugins_url” function into “_setup_constants()” function into initialization…

Can you fix this one? Because we can’t filter each WordPress functions used in AnsPress initialization.

Thanks !