I have a problem where I've been able to include a custom css in the section of my wordpress theme with the following code:

function load_my_style_wp_enqueue_scripts()
{
wp_register_style('my_styles_css', includes_url("/css/my_styles.css"));
wp_enqueue_style('my_styles_css');
}
add_action('wp_enqueue_scripts','load_my_style_wp_enqueue_scripts');

But the order in the source code is as follows:

<link rel='stylesheet' id='my_styles_css-css'  href='http://...folderA.../my_styles.css?ver=3.1' type='text/css' media='all' />
<link rel="stylesheet" id="default-css" href="http://...folderB.../default.css" type="text/css" media="screen,projection" />
<link rel="stylesheet" id="user-css" href="http://...folderC.../user.css" type="text/css" media="screen,projection" />

I want my_styles_css to be the last file to load, overriding default and user files. I've tried to achieve this by modifying wp_enqueue_style in different ways, but without any success. I've tried:

wp_enqueue_style('my_styles_css', array('default','user'));

or

wp_enqueue_style('my_styles_css', false, array('default','user'), '1.0', 'all');

I've seen some related questions without answer or with these last 2 methods that are still failing for me.

The function above is part of a plugin that I've got enabled in my wordpress installation.