I have no clue what JavaDoc is, but I'll share what we do for comments in our classes:
In .NET you can create something called a Region. In your code behind, you basically do this:
#Region "Comments
#End Region
What this does is create an expandable node within your code that can store data! We have one for comments, one for declarations, one for properties, and one for the actual class code in each class.
This way, you can put as much documentation as you want within the class file itself, but only see it when you want to.
hth
D'Arcy