Changing site from asp to php- preserve page rank

[jessnoonyes]

Hi all! I'm thinking about changing a site over from asp to php, but I'm concerned about the site's page rank, which is pretty good right now. I know that changing all of the file extensions from index.asp to index.php will pretty much destroy it.

I'm wondering if I can rewrite the page extension with htaccess back to .asp even though it's a php page. And do you any of you know if this will preserve the current page rank?

thanks for any advice!