you can change the urlRewrite property of the blogs provider to look something like this:
add name="Blogs" urlRewriteFormat="[Publication_Date]/[Category]/[Title].aspx" ...
Make sure you make the category input required in this situation. On the side note, the square brackets in the urlRewriteFormat represent a value that will be replaced by a metafield value. So you can add any of the module supported metafields to be part of the url.
I hope you'll find this information helpful. Let us know if there is anything else we can do for you.
All the best,
the Telerik team
Check out Telerik Trainer
, the state of the art learning tool for Telerik products.