Customize Facebook OGP tags in WordPress SEO by Yoast plugin

Hello,

I am trying to customize the Facebook OGP metatags generated by Joost’s excellent WordPress SEO plugin. I can find where I can set the description and the image, but I cannot find where to set the other attributes or even add some that aren’t included by default. My client’s website is for her business so I am trying to add all the appropriate tags. I found this:

public function type() {
		if ( is_singular() ) {
			$type = wpseo_get_value('og_type');
			if (!$type || $type == '')
				$type = 'article';
		} else {
			$type = 'website';
		}
		$type = apply_filters( 'wpseo_opengraph_type', $type );
		echo "<meta property='og:type' content='".esc_attr( $type )."'/>\n";
	}

so the $type = wpseo_get_value('og_type'); part makes me believe I can set a custom type somewhere but where?

EDIT: Obviously I can just hack the plugin, which I have in fact done, but I would rather use it properly so updating is not a pain.

Thanks!