hello romeo,
i modified deploy\ejb3-interceptors-aop.xml . search for the PoolClass annotation, maxSize is the value to limit amount of instances:
<aop>
...
<domain name="Stateless Bean">
...
<annotation expr="!class(@org.jboss.annotation.ejb.PoolClass)">
@org.jboss.annotation.ejb.PoolClass (value=org.jboss.ejb3.StrictMaxPool.class, maxSize=15, timeout=10000)
</annotation>
</domain>
...
</aop>
greets
robert