HELP: Rewrite rules won´t work after WP generation

I´ve read all about “About permalinks” in Codex. I tried to request some help here in the forums, in both threads (see them in http://wordpress.org/support/profile/21486)

I´ve noticed that my WordPress 1.5.1.2 won´t generate a working permalink structure in .htaccess. I´m using a structure like

/archivos/%year%/%monthnum%/%day%/%postname%/

After a deep inspection in .htaccess I´ve noticed that WP does not generate rules for all rewriting posibilities

/archivos/%year% Works fine. Example: http://www.sahw.com/wp/archivos/2005

/archivos/%year%/%monthnum%/ Works fine. Example: http://www.sahw.com/wp/archivos/2005/06/

/archivos/%year%/%monthnum%/%day% Works fine. Example http://www.sahw.com/wp/archivos/2005/06/01

/archivos/%year%/%monthnum%/%day%/%postname%/ WON´T WORK. Example: http://www.sahw.com/wp/archivos/2005/06/01/criptored_resumen_mes_de_mayo_de_2005/

At this point, I´ve checked Rewrite rules. You can see them in PasteBin

I suspect that WP does only generate /archivos/%year%/%monthnum%/%day%/ structure, as %postname% is not listed in my WP .htaccess file.

I used to have ([_0-9a-z-]+) syntax in my former WP 1.2 rules, and I can´t see this alphanumeric with _ and – post title rule in the file Worpress generates.

Could someone provide me with a working WP 1.5 .htaccess rules for /archivos/%year%/%monthnum%/%day%/%postname%/ structure?

Thanks in advance