Hi Wolfgang,
To tell you the truth, I don't know enough about clustering to give a definitive answer, but I would say that an important consideration is whether the application is stateful. Clustering uses caching to share state among machines, so, if you need to share state, I think you would have a lot of work to reach your goal. In that case, I think you might want to adapt your client to use EJBs, with all of their built in infrastructure, instead of invoking Remoting directly. If you don't have shared state, then I guess you could just start up a Remoting server in each AS instance, but that still doesn't give you load balancing. Again, you might be better off using the built in EJB mechanisms.
-Ron