Fix a repeating background to prevent scrolling

Theme: Twenty Twelve
Child Theme: Yes
Website: http://packerlandwebsites.com/responsive/

Issue: I would like to have the background stay fixed and not scroll when a visitor is looking at the page. This is for a repeating background image. On a regular website I would place this in the head:

<STYLE>
<!--
BODY {background-attachment: fixed;}
//-->
</STYLE>

But, I still need to figure a few things out in WordPress. I appreciate your help