Re: ratio_3_2を使用させていただいております。

<?php
	$WS_theme_config = ClassRegistry::init('ThemeConfig');
	$WS_theme_config_data = $WS_theme_config->findExpanded();
	if( ( !empty( $WS_theme_config_data['logo'] ) ) && ( empty( $WS_theme_config_data['logo_alt'] ) ) ) {
		$this->BcBaser->logo(array( 'alt' => $this->BcBaser->siteConfig['name'], 'class' => 'navbar-brand'));
	} elseif ( !empty ($WS_theme_config_data['logo'] ) ) {
		$this->BcBaser->logo(array( 'alt' => '', 'class' => 'navbar-brand'));
	}
	if( !empty( $WS_theme_config_data['logo_alt'] ) ) {
		echo '<a class="navbar-brand" href="' . $this->BcBaser->getUrl('/') . '">' . $WS_theme_config_data['logo_alt'] . '</a>';
	}
?>