It is showing up, I think, it's just not styled like the other modules. So, there is a part of your CSS that has this:

.module-customtext, .module-typelist, .module-tags_list, .module-pagesummary, .module-calendar, .module-syndicate, .module-powered, .module-time {
-moz-background-clip:border;
-moz-background-inline-policy:continuous;
-moz-background-origin:padding;
background:#FFFFFF none repeat scroll 0 0;
border:1px solid #E5E5E5;
margin:0 0 10px;
padding:10px;
}

It's specifically saying which modules get that nice white background and such.

Now, I think it would be best if that was changed to:

div.module-section-one .module {
-moz-background-clip:border;
-moz-background-inline-policy:continuous;
-moz-background-origin:padding;
background:#FFFFFF none repeat scroll 0 0;
border:1px solid #E5E5E5;
margin:0 0 10px;
padding:10px;
}

That way, all modules you put in that section from now on would have the same styling, and they wouldn't have to all be specifically coded for. If that is not the effect you want, you can add .module-active to the list of module classes in the previous CSS.