Authentication Services module
Drupal Services is a bit strange in that it doesn't seem to fall back to calling the user_access() function. Instead, I always provide a custom access callback function, and in it usually just make a call to user_access(). Try this:

'doli' =&gt; [
        'create' =&gt; [
            'callback' =&gt; 'custom_api_create_user',
            'access callback' =&gt; 'example_access_callback',
            'access arguments' =&gt; array('administer access control'),
            'access arguments append' =&gt; TRUE,
            'access callback file' =&gt; array(
              'type' =&gt; 'inc',
              'module' =&gt; 'example',
              'name' =&gt; 'example.resource',
            ),
                'args' =&gt; [
                [
                    'name' =&gt; 'data',
                    'type' =&gt; 'struct',
                    'description' =&gt; 'data',
                    'optional' =&gt; FALSE,
                    'source' =&gt; 'data'
                ]
            ],
        ]
    ]


Then make a file called example.resource.inc in your module's folder, and place this code into it:

function example_access_callback($permission) {
  return user_access($permission);
}