I am trying to post some source code on a WordPress.com blog. WordPress actually makes posting syntax-highlighted code quite easy--you wrap the code in a `[sourcecode]` block, optionally specify the language with the `lang` attribute, and you're good.

I've never had a problem with this before, but I recently found an issue I can't fix. I'm trying to render some source code on the blog with the following.

```
[sourcecode lang="html"]
<iframe src="http://someserver.edu/somescript.php?id=223"
        marginwidth="0" marginheight="0" frameborder="0" 
        scrolling="no" width="210px" height="60px"></iframe>
[/sourcecode]

```

When I try to preview the post, the HTML gets stripped from the `[sourcecode]` block. When I try to escape the `<` and `>` characters, the code block is rendered, but the raw text is shown without interpreting the encodings (so you see `&lt;` instead of `<`, etc).

I'm guessing the original HTML is being stripped as rendering an iframe could lead to security vulnerabilities. But I *don't want* to render the iframe, I want to render the code behind the iframe, which should not present any security issues. How can I tell the blog to render my source code correctly?