Display numbers on Menu-created categories

Hello!

I’m just trying out WordPress 3 and the new Menu functions, so far it’s awesome and I love it. I installed this blog for a friend who is an artist, and this is how it’s looking so far:
https://lnx.xradicaldreamers.net/wt/

I’m using the MODULARITY LITE theme, looks great huh?

The “filter by category” thing is done using a Menu, which makes it look so good in Modularity Lite, the regular Category Widget just looks old and boring.

Here’s my question. I can’t find how to make the categories display the number of entries in this category, you know, at the side of each category in a parenthesis, like this other blog:
https://lnx.xradicaldreamers.net/beliteratura/

How do I make WordPress 3 Menus display the number of entries in Categories? I think it helps a lot to the blog and I can’t stand not having it :P!

Thank you very much for your time. ??