Fancybox + Bursting Pipe Ad

We're using Fancybox to throw up essentially an interstitial ad. The page loads, then Fancybox loads over it, and displays our ad content. For most ad content we've put up, this has worked (hand-coded links/images, DoubleClick content, etc). But ads from Burst Media seem to cause no end of headache.

As soon as Fancybox loads, the Burst ad takes over, and does it's document.write() to the page. This (as far as I can tell) dumps everything else, and displays only the ad content.

To make matters stranger, the same ad code works correctly in inline placed ads on our page.

The only thing I can think is that because the Burst content is missing an i开发者_开发技巧frame, it's causing havoc on the page; but because it works in other places, I'm becoming frustrated and confused.

Any suggestions?

EDIT: Ad content comes from an admin where employees paste in the appropriate HTML. It is added to the page via PHP directly.

For those that may need it in the future, you do need an iframe, as @Pointy suggested; here's the template for the iframe portion:

<iframe src="http://bs.serving-sys.com/BurstingPipe/adServer.bs?cn=rsb&c=<VALUE_OF_C>&pli=<PLI_ID>&PluID=0&w=300&h=250&ord=[timestamp]&ifrm=2&ucm=true&z=0" width=300 height=250 marginwidth=0 marginheight=0 hspace=0 vspace=0 frameborder=0  scrolling=no bordercolor="#000000">
    <script src="http://bs.serving-sys.com/BurstingPipe/adServer.bs?cn=rsb&c=<VALUE_OF_C>&pli=<PLI_ID>&PluID=0&w=300&h=250&ord=[timestamp]&ucm=true&z=0"></script>
    <noscript>
        <a href="http://bs.serving-sys.com/BurstingPipe/BannerRedirect.asp?FlightID=<PLI_ID>&Page=&PluID=0&Pos=5500" target="_blank"><img src="http://bs.serving-sys.com/BurstingPipe/BannerSource.asp?FlightID=1825049&Page=&PluID=0&Pos=5500" border=0 width=300 height=250></a>
    </noscript>
</iframe>

Please note that essentially, the only difference for the iframe is that the src attribute has an ifrm=2 value included in the querystring. Everything else should be the same.