.htaccess replace hyphens with underscores

programming
1

Alright, after I moved to MT, all links to my old archives broke. I was trying to fix this with a little mod_rewrite and some elbow grease, but came upon a bit that I couldn’t figure out.

I need to replace all the hyphens with underscores when I rewrite the filename.

Right now, it looks like this:

RewriteEngine On
RewriteBase /archives/
RewriteRule  ([0-9]{4})/([0-9]{2})/([a-zA-Z_-]{1,15})(.*).html   http://nokrev.com/older/$1/$2/$3.php

Which redirects something like
nokrev.com/archives/2005/03/fresh_bananas_theme.html
to
nokrev.com/older/2005/03/fresh_bananas_t.php

but what I need is it to change
nokrev.com/archives/2005/03/fresh-bananas-theme.html
into the second one.

Sorry, I can’t say it well, but I’m sure it’s easy to understand.

Thanks a bunch for your help,
Jeff Wheeler