title: Spring 3.1 PropertySourcesPlaceholderConfigurer and conditional import
body: <p>Looking at the new spring property support in 3.1 ( <a href="http://blog.springsource.org/2011/02/15/spring-3-1-m1-unified-property-management/" rel="noreferrer">http://blog.springsource.org/2011/02/15/spring-3-1-m1-unified-property-management/</a> ), it looks like this should be possible:</p>
  
  <pre><code>&lt;context:property-placeholder location="/WEB-INF/application-customer-dev.properties,classpath:application-customer.properties" ignore-resource-not-found="true"/&gt;
  
  &lt;import resource="classpath*:com/x/core/security/security-${login.security}.xml"/&gt;
  </code></pre>
  
  <p>where login.security is in application-customer-dev.properties as:</p>
  
  <pre><code>login.security=dev
  </code></pre>
  
  <p>(and security-dev.xml does exist in the appropriate place).  I am missing something though, as login.security is not able to be resolved.  I would expect this behavior in versions of spring prior to 3.1, but it looks like this should be valid with 3.1 (which we are using)?  </p>