Hi giann_mga,
If you scaffold a Spring 3 application in ME4S, you already have the <mvc:annotation-driven> configuration in your web-context.xml file. Also, when you scaffold, if you allow the scaffolding to configure your project’s dependencies, you will indeed have a JSR 303 implementation on the classpath because the Hibernate 3.5 dependency we add uses the hibernate-validator-4.1.0.Final.jar.
However, we did not use the @Valid annotation so you would need to find spring examples from springsource or other resources on exactly how to use that from within your code.
I hope this helps.