[Plugin: bbPress] Adding more fields for post content

I’d like to add some additional fields to the initial forum post screen that then pass through and are displayed along with the post.
I have so far located in form-topic.php where the input text box is located and then in bbp-topic-template.php the following function which i believe is pulling in the content from this text box:

function bbp_get_form_topic_content() {
		global $post;

		// Get _POST data
		if ( 'post' == strtolower( $_SERVER['REQUEST_METHOD'] ) && isset( $_POST['bbp_topic_content'] ) )
			$topic_content = $_POST['bbp_topic_content'];

		// Get edit data
		elseif ( !empty( $post->post_title ) && bbp_is_topic_edit() )
			$topic_content = $post->post_content;

		// No data
		else
			$topic_content = '';

		return apply_filters( 'bbp_get_form_topic_content', esc_textarea( $topic_content ) );
	}

What I want is to be able to do is to pull in the value inputted into a couple of additional fields/checkboxes.

Can anyone give me a pointer on where I should insert the field name? Is it even possible without breaking things?

Thanks