The first thing to confirm is whether you can get a CC or BCC with a normal (non select) specification:
(Make sure you rename the "select" field to something else to do this test).Code:<input type="hidden" name="cc" value="firstname.lastname@example.org" />
Also, are you getting error alerts (have you set DEF_ALERT)? If $TARGET_EMAIL doesn't match the email address you specify in "cc" or "bcc" it won't send the mail (but you will get an alert).
Once you've got "cc" working from a normal hidden field, it should work from the select field.