Spring Method Level Security fails on second call

问题

I want to use method level security on my GWT application. I'm trying to use Spring Security 3.1, as I found a working example here, but it doesn't use form-login. After reading this answer the first method call successfully obtains the SecurityContext, but then clears it before the next call:

[org.springframework.security.web.context.HttpSessionSecurityContextRepository] - Obtained a valid SecurityContext from SPRING_SECURITY_CONTEXT: 'org.springframework.security.core.context.SecurityContextImpl@6fe9f089: Authentication: org.example.MyAppName.server.auth.MyAppNameUserAuthentication@6fe9f089'
...
[org.springframework.security.access.intercept.aspectj.AspectJMethodSecurityInterceptor] - Authorization successful
...
[org.springframework.security.web.context.SecurityContextPersistenceFilter] - SecurityContextHolder now cleared, as request processing completed
...
[org.springframework.security.web.context.HttpSessionSecurityContextRepository] - SecurityContext is empty or contents are anonymous - context will not be stored in HttpSession.
[org.springframework.security.web.context.SecurityContextPersistenceFilter] - SecurityContextHolder now cleared, as request processing completed
...
[org.springframework.security.web.context.HttpSessionSecurityContextRepository] - HttpSession returned null object for SPRING_SECURITY_CONTEXT

The second call happens straight after the first and just after the user logs in.

Is it because I followed the other answer and removed <http pattern="/MyAppName/**" security="none" /> and added <intercept-url pattern="/MyAppName/**" access="permitAll()" />?

My filters are as follows:

<http pattern="/favicon.ico" security="none" />

<http access-decision-manager-ref="accessDecisionManager" use-expressions="true" auto-config="false" entry-point-ref="LoginUrlAuthenticationEntryPoint">
  <form-login login-page="/Login.html" always-use-default-target="true" default-target-url="/Main.html?gwt.codesvr=127.0.0.1:9997" />
  <intercept-url pattern="/Login.html" access="permitAll()" />
  <intercept-url pattern="/Login2.html" access="permitAll()" />
  <intercept-url pattern="/MyAppName/**" access="permitAll()" />
  <intercept-url pattern="/**" access="isAuthenticated()" />
  <logout delete-cookies="JSESSIONID" logout-success-url="/Login.html" />
  <remember-me token-validity-seconds="86400" key="key" user-service-ref="userDetailsService" />
</http>

Following the example I obtained I use AspectJ for the global method security, but would not use it if I could get that working:

<global-method-security secured-annotations="enabled" pre-post-annotations="enabled" mode="aspectj" proxy-target-class="true" >
  <expression-handler ref="expressionHandler"/>
</global-method-security>

Thank you for taking the time to read this

Please let me know if more detail is needed.