Ok, try this and let me know if it works. I just put it together and haven't tested it thoroughly yet.
In showthread.php:
Find:
PHP Code:
} elseif ($bbuserinfo['showquickreply']==0) {
$replybox='';
} else {
$textareacols = gettextareawidth();
After it add:
PHP Code:
if ($bbuserinfo['sendtoforumdef']) {
$sendtoforum = 'yes';
} else {
$sendtoforum = '';
}
Then put this in your showthread_replybox:
PHP Code:
<input type="hidden" name="sendtoforum" value="$sendtoforum">