How to preserve .htm urls withour redirect.

I switched to wordpress and want to preserve old pages whitch have PR and were created years ago and have .htm like urls. Can I do that without 301 redirect?

I just want to put their content to new WP posts and rewrite those posts urls to .htm i did that once but there were no possibility to choose .htm like urls. What to do?

Now i have half of my plastic surgery site still static, which is very hard to work with.