Argue!'s graphical interface was considered too unfamiliar for the intended users, and its underlying argumentation theory was not sufficiently transparent. Therefore the ArguMed-system was designed with a template-based user interface: the user gradually constructs arguments, by filling in templates, each corresponding to an argument move, such as making a statement.
In fact, the system described in this paper is the second version of the ArguMed-system - the first version is described by Verheij . Two drawbacks of the previous version have been solved. First, though the arguments were presented graphically, argument attack was not. It was graphically shown that an argument was defeated by an attacking argument, but not by which argument. Second, in the argumentation theory underlying ArguMed's first version, it was not possible to put at issue that a particular statement was a reason for another statement, or that a statement was an exception.
Solving the first of these two drawbacks has led to a new graphical representation of the arguments, in which argument attacks are shown, and to a change in the argumentation theory, viz. the introduction of a novel notion of an argument, viz. that of a dialectical argument. Briefly, a dialectical argument is an argument in which attacks (and counterattacks) are incorporated. A simple example is shown in Figure 1. The shown argument expresses that the (prima facie) reason that Peter has violated a property right does not justify its conclusion that Peter has committed a tort, as a result of the exception (of Pollock's  undercutter-type) that there is a ground of justification for Peter's act.
The full paper has been presented at The Seventh International Conference on Artificial Intelligence and Law, and contains a detailed explanation of dialectical arguments and more examples.
See the details of the full paper.
Reference for the abstract:
Verheij, Bart (1999). Automated Argument Assistance for Lawyers (abstract). BNAIC '99. Proceedings of the Eleventh Netherlands/Belgium Artificial Intelligence Conference (eds. Eric Postma and Marc Gyssens), pp. 269-270. Maastricht.