[Plugin: Contact Form 7 to Database Extension] form fields added via wpcf7_add_shortcode hook not ad

I am adding a dropdown field to the form via shortcode which eventually will be populated from custom posts. currently it’s just dummy code:

function msug_wpcf7_instrumente_listgenerator() {
    /* need to produce html like this:
    <span class="wpcf7-form-control-wrap menu-645"><select name="menu-645" class="wpcf7-select"><option value="one">one</option><option value="two">two</option></select></span>
    so here we go:     */
    $instrumentelist = "<span class=\"wpcf7-form-control-wrap menu-instruments\"><select name=\"menu-instruments\" class=\"wpcf7-select\"><option value=\"test1\">test-1</option><option value=\"test2\">test-2</option></select></span>";
    return $instrumentelist;
}
wpcf7_add_shortcode('msug_wpcf7_instrumente', 'msug_wpcf7_instrumente_listgenerator');

and coinsequently I add [msug_wpcf7_instrumente] to the form which displays properly.

however, the field does not get inserted into the database (while all other “normal” fields do get inserted).

any advice on this?

http://wordpress.org/extend/plugins/contact-form-7-to-database-extension/