Help with duplicate issue in WP

Hello there… in my photography blog I just changed my permalink in WP to a more structured solution that better cover and describe the variety of pictures and images displayed.

So i moved from…

to…

I use Platinum SEO pack plugin in WP and I have everything re-directly 301 smoothly to the new url.

If I digit the old url in the browser I got the new one and the correct page.

Also the canonical link is created correctly and is the new one.

All look perfect but… Google webmaster tool is finding out hundreds of duplicate content considering wrongly the old url and the new url as different pages (and so obviously same title and description).

What I should do?

No one reply to this… anyway it was just matter of time… today there are no errors anymore.

Regarding this issue and experiment I just want let you know that today there is not anymore any issue with duplicate content in my website but the pagerank of all the changed url post in WP is now 0 (before was 2) like if it was a brand new page with new url.
That was really bad! and Google states exactly the opposite saying that a correct 301 redirection does not alter the old pagerank.