How to use the day archives

I want to almost exactly what the Codex advises against:

Note that even though one might never make more than one posting a day, and thus wishes to use e.g., %year%%monthnum%%day%, links so generated will however be interpreted as the archive of all posts for that day. One needs at least %year%%monthnum%%day%%hour% to target an individual post.

For a subsection of my site (not currently WordPress, but thinking of moving), andrewsteele.co.uk/blog, my links are exactly like that. So I tried creating categories called ‘blog, 2009, August 2009 and then putting posts as the actual days, and it all works except that clicking on links to the post, correctly rendered, results in an error 404 on the test version of my site.

How can this be rectified?

I’d also quite like it if I could have a general archive of things from all categories at andrewsteele.co.uk/archive/yyyy/mm/ or similar…is it possible to do this whilst having permalinks to individual posts being andrewsteele.co.uk/category/postname?

Many thanks!