How to start specified feature spring version in PAX-EXAM

[Ken Longnan]

Hi,

I want to start feature spring version 3.2.4.RELEASE in PAX-EXAM.

I try to do following way, but it doesn't working:
 features(

maven().groupId("org.apache.karaf.assemblies.features").artifactId("enterprise").type("xml")
                                .classifier("features").version("2.3.5"),
                        "transaction", "jndi", "jpa",
"spring/3.2.4.RELEASE"),

How to archive it?

Thanks & BR,

Ken