Captcha Security for Item Comment Form Osclass

Osclass item comment form is lack of Captcha security…How to integrate captcha security for this section? I have clonned / copied

<?php osc_show_recaptcha(); ?>

from user-register.php, but it does not working…no function!

did you configure captcha or akismet?
oc-admin/index.php?page=settings&action=spamNbots

Captcha doesn’t work on comment form, it is there for contact form. We need make some changes for that.

Yes, I configured of course, but spam registration not solved.
Finally I have installed **[Advanced CAPTCHA] plugin of WEBMODS,
Now spam registration stopped.