Trying to modify existing form but add Captcha functionality

I have a simple form with a few fields. I would like to add Captcha functionality to it since I'm getting some malicious attacks which is resulting in invalid database records. I have been using the validations built into DW CS4 but doesn't prevent all the bad stuff.

So I tried following the directions for Form Builder. Cleared out my validations code, made the form look normal again, then positioned my cursor inside the form and Inserted Form Builder. I saw the preview of my form but there is no option for putting Captcha in there.

Am I doing something wrong?

You will need to add a new fieldset to the form, it is called security within Form Builder. Once you apply the security portion you will have captcha and a security question in the form, you can edit this fieldset to remove the question and leave only the captcha for the form security.

I'm not seeing "Security" as an option.

Here's the procedure I'm following:
In Source Code mode in DW I place my cursor on the line below the <form> line
I click Insert / WebAssist / CSS Form Builder / Insert Form
Available choices from "Choose a Form": New From Blank, Log in, Registration, Contact, eCommerce, Web Designers.

So what am I doing wrong?

In design view you should select the form tag, there is a blue border around the CSS Form Builder forms, you should select this. When you do the property inspector should have the options for you to edit the form (preset), edit the contents, or edit the design.

You will want to edit the contents of the form, then choose to add a new group to the form, when it is added go to the bottom of the interface and for the category choose Security, then for type choose Security also.

This should add the captcha and security question, you can then edit the group if you want to remove the security question and leave just the captcha there.