bp_document_prepare_attachment_for_js( array $response,  $attachment,  $meta )

function bp_document_prepare_attachment_for_js( $response, $attachment, $meta ) {
	if ( isset( $response['url'] ) && strstr( $response['url'], 'bb_documents/' ) ) {
		$response['icon'] 	= includes_url() . 'images/media/default.png';
		$response['type'] 	= 'text';
		$response['sizes'] 	= array();
	}

	return $response;
}