My client has an iframe-type page that utilizes some PHP code to grab content from a 3rd party to display on the page. This "page" has a few navigation buttons that serve up new information.

We're using Joomla's SEF and mod_rewrite functions. Let's assume my Joomla article is located at http://www.mysite.com/joomla-article. When clicking on the iframe navigation, the new URL should become http://www.mysite.com/joomla-article?p=newinfo, but instead it goes to http://www.mysite.com/?p=newinfo which redirects to the frontpage.

I've attempted adding the following line and tweaking it here and there, but I'm not having much luck. Can anybody shed some light on this for me?

Code:
RewriteRule ^/?p=([a-z]+)$ /joomla-article?p=$1 [R=301,L]