Argumentation in multi-agent systems provides both a mechanism for agent reasoning under uncertainty and conflicting information as well as for communication in a more elaborate way, allowing agents to understand each other through the exchange of additional information when compared to other forms of agent communication. Even though argumentation techniques can play an important role in multi-agent systems, little research has been carried out on the issues in integrating argumentation techniques and agent-oriented programming languages, which would allow the development of practical applications taking advantage of such combined techniques. In this work, we present an argumentation framework developed on the basis of an agent-oriented programming language. We cover mainly the practical aspects of such integration, focusing on the knowledge representation expressivity resulting from it. Our approach allows the development of multi-agent applications where agents are able to use arguments in their decision-making processes as well as for communication. The framework has been successfully used as part of the development of a healthcare multi-agent prototype application.