Problem with custom post types - Select menu options won't save or display properly

[A+Consulting]

I've run into a problem in the Wordpress Anthology book, and I swear I think the book contains a misprint. I've tried the exact code (as seen below) from the book and cannot get it to function correctly. I asked a developer friend to take a look, and he agreed that there is something afoot. But neither of us could track it down in the book's errata page or anywhere else.

Chapter 4 explains how to build a custom post type. Among other things, the example shows being able to use a pull-down to select the 'conference session venue' using the following code:

function conference_session_meta(){
    global $post;
    $custom = get_post_custom($post->ID);
    $conference_session_room = $custom["conference_session_room"][0];
    $conference_session_date = $custom["conference_session_date"][0];    
?>
    <p>
        <label>Room</label><br />
        <select name="conference_session_room">
            <option value="Grand Ballrom">Grand Ballrom</option>
            <option value="Plenary A">Plenary A</option>
            <option value="Plenary B">Plenary B</option>
            <option value="Theatre">Theatre</option>
        </select>
    </p> 

However, when following the (full) example, the options are not saved when the selection is made and the post is published.
And when the page refreshes, the selection made is not shown as selected in the pull-down (I tried to select "Plenary A", but the 1st option "Grand Ballroom" still appeared.)

Can anyone help us me figure out how to properly save these options when using a select menu?

Thanks in advance,

ben