In the realization of agent-based applications the developer generally needs to use heterogeneous agent architectures, so that each application component can optimally perform its task. Languages that easily model the heterogeneity of agents' architectures are very useful in the early stages of the application development. This paper presents HEMASL, a simple meta-language used to specify heterogeneous agent architectures, and sketches how HEMASL should be implemented in an object-oriented commercial programming language as Java. Moreover, the paper briefly discusses the benefits of adding HEMASL to CaseLP, a LP-based specification and prototyping environment for multi-agent systems, in order to enhance its flexibility and usability.