new To htaccess - Quick questions

I have this rule set up:

I am taking an all html site and making it dynamic with php. So I am using this to forward all html requests to php pages. My problem is when some one goes to "www.mysite.com/topic/" the php page will show since the html dosent actually exsist. I tried making DirectorIndex to be index.html but that dosent work. Is there a solution to make a index.html page that physically isnt there be the DirectoryIndex and point to the php?

Huh? What do you want to be displayed when someone goes to /topic/ ? /topic/index.html? /topic/index.php /index.php/r=topic ?