Feature request: defer permalinks structure

I don’t know if I should call this a bug or a feature request, but when you write a post and choose not to publish it immediately, but later on (or before), the draft is saved with the permalink (if you customize Permalinks in Settings and set it to a date based structure) showing the date you started writing, I think it should automatically update with the publishing date.

For example, I start writing a post on 31/01/2009, it automatically saves a draft while I write it and the permalink looks like this: blog.example.net/2009/01/31/post-title/. I want it to be published on 31/01/2010, so I defer the date on the publishing settings, but the permalink still reflects the previous date.

So I’d like to request an automatic upgrade on the permalink if you make changes on the publishing date…