XML-RPC and Custom Fields starting with "_"

Hi all

I’m using the IXR_Client from wordpress code to use the IXR petitions, posting works fine except that custom fields starting with _ doesn’t work

$post =
	array(
		"title" => $datap[2],
		"description" => $datap[3],
		"wp_page_parent_id" => $parent,
		"wp_page_order" => $datap[4],
		"custom_fields" => array(
			array(
				"key" => "_aioseop_title", "value" => $datap[6]
			), array(
				"key" => "_aioseop_description", "value" => $datap[7]
			), array(
				"key" => "_aioseop_keywords", "value" => $datap[8]
			), array(
				"key" => "_aioseop_titleatr", "value" => $datap[9]
			), array(
				"key" => "_aioseop_menulabel", "value" => $datap[10]
			)
	)
);

where $datap is an array with respective post data.

The posting is working just the custom fields starting with “_” doesn’t work, they works if doesn’t have a “_” as prefix