Spring based configuration with user specified expression manager

It is possible to configure the expressionManager property on the org.activiti.spring.SpringProcessEngineConfiguration bean. But when it comes to creation within org.activiti.spring.ProcessEngineFactoryBean at the initializeExpressionManager method, the configured ExpressionManger gets overridden.

A possible solution is to check if an ExpressionManager is configured before it gets overridden.

...
protected void initializeExpressionManager() {
if (processEngineConfiguration.getExpressionManager() == null && applicationContext != null)

}
...