FAPI - fill form fields on ajax callback (again)

Hello. I'm trying to make a quite simple task in my module - load values from DB using one value. Saying simple: there is a form with a bunch of fields. When I fill email field I need to load it's settings and fill the form with them. That simple.
But I can not make my button change value in a textfield.
What I have:

function mymodule_form( $form, &$from_state){
  if(isset($form_state['values']['your_name']))
	{
		$name_value = $form_state['values']['your_name'];
	}else{
		$name_value = "";
	}
	
	$form = array();
	$form['your_name'] = array(
		'#title' => t('Your or your company name'),
		'#type' => 'textfield',
		'#value' => $name_value,
		'#prefix' => '<div id ="subscribers-name">',
		'#suffix' => '</div>',
	);
	$form['load_settings'] = array(
		'#type' => 'button',
		'#value' => t('Load my settings'),
		'#submit' => 'simplenews_mod_load_subscriptions',
		'#ajax' => array(
			'wrapper' => 'subscribers-name',
			'callback' => 'simplenews_mod_load_subscriptions_ajax',
			'method' => 'replace',
		)
	);
  return $form;
}
function simplenews_mod_load_subscriptions( &$form, &$form_state)
{
	$form_state['values']['your_name'] = "loaded value"; 
	$form_state['rebuild'] = TRUE;
}
function simplenews_mod_load_subscriptions_ajax( $form, &$form_state)
{
	return $form['your_name'];
}

With this code I expect that the only text field in my form will be filled with loaded value text when I press the Load my settings button that's all. But it does not. What am I doing wrong? Please suggest. I'm struggling with this for over 3 days.
Thank you