Maintain Permalinks moving from Blogger to WordPress

Hello and sorry for my poor english:

I´ve done a migration from Blogger to WordPress 2.2. Everything is ok, except the permalinks.

I´ve redirected my old blog (http://directivamarco.blogspot.com) to the new domain (http://directivamarco.es/) and it works fine.

I´m trying to maintain the permalinks of my old posts, but wordpress creates new post slugs based on the post titles. I was searching and I found this post where the autor gives a solution for WordPress 2.0.4.

I´ve tried to edit my archive blogger.php, but it seems that is totally new.

Can anybody help me?

Thank you very much.