Well, I think I can answer your main question.
1. In the LogCat view of Eclipse, make sure that the filters view is visible (in the top right corner of this view there is a button that shows/hides the filter pane).
2. Click the green plus sign in the filter pane.
3. Fill in the Filter Name and Application Name fields.
Actually that was too easy - my answer looks like something from eHow - so I suspect that this isn't what you meant (or maybe you had the filter pane hidden).
I would also add that the Application Name field has been there for as long as I remember - definitely prior to Android 4.0.
I can't help you with the other problem: that the 'Application Name' field/column is sometimes blank on log lines from your application. I haven't figured out why the lines sometimes include the Application Name and sometimes don't.
So, that pretty much makes it useless to filter on that field. Hopefully someone else can resolve that mystery.