Lighttpd

I am trying to do a simple alias like this

$HTTPhost == "my.host.com" {
server.document-root = "/home/sites/my.host.com/php/"
alias.url = ( "/html/" => "/home/sites/my.host.com/html/" )
}

It works with php and html files in the php directory, but when I redirect from /index.php to /html/en/index.html, the browser tries to download the file.

If I create the html file in the php directory it displays fine. I have the correct mime settings.