Help with complicated redirect on WP blog site?

[irened]

Hi, this might be a boneheaded question but I'm having trouble with a type of permalink redirect and can't find the answer anywhere online.

I changed my Wordpress blog urls twice:

1. First from sitename/blog/date/postname/ format to sitename/blog/postname/ format.

For that I used Dean's Permalink Migration plugin and it worked fine.

2. Then, I switched my site to a completely WP-based site with a static front page and the posts on a blog page, so everything is in the public_html.

So now everything needs to end up at sitename/postname/.

This Permalink Migration plugin setting:

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

Works for:

/blog/postname/ and
/date/postname/

but not for

blog/date/postname.

Do I need to use the htaccess to individually 301 redirect all of the posts with that last url format, or is there one command that will do all of those without messing up the others?

Thanks, if anyone can help. :)