Cannot locate BeanDefinitionDecorator for element [scoped-proxy]

I am trying to implement an object that needs to be globalSession scoped (Portlet). When I add the following bean definition to my context I receive the following error:

java.lang.IllegalArgumentException: Cannot locate BeanDefinitionDecorator for element [scoped-proxy].

Bean Definition:

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schem...-beans-2.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

<bean id="userCache" class="albany.edu.portlets.required.surveys.model. UserCache"
scope="globalSession">
<aop:scoped-proxy/>
</bean>

What am I missing?


Any help is greatly appreciated.