Extra page URL paramaters

Hi,
Let’s say I have a WP page at domain.com/mypage/
What I need to do is supply this page with extra paramaters in the URL. I can get this working fine by doing domain.com/mypage/?one=a&two=b

But, what I want to do is to just have domain.com/mypage/a/b/. Whenever I visit page URLs which have more paramaters added to the end of the URL it always comes up as page not found.

I’ve tried adding a rewrite rule to my .htaccess file but that didn’t work at all. Unless I was doing it wrong. I’m guessing that some sort of rewrite rule needs to be added to .htaccess but I can’t get it working.

Can anyone help me out here?

Thanks!