switch over String in function

Executive Summary: if I try to implement switch over String as per Java 1.7, inside of DRL function, compilation of DRL fails, but the error message would suggest that actually switch over String should work.

Steps to reproduce
Have a DRL file with function with String parameter and inside the function a switch over the parameter, for example

rule "Stupid rule over String"
when
	String()
then
	System.out.println("Hello world");
end

function void theTest(String input) {
	switch(input) {
		case "Hello World" : 
			System.out.println("yep");
			break;
		default :
			System.out.println("uh");
			break;
	}
}

Have simple code to compile DRL for default KieBase, for example snippet:

String input = "Hello World";
// Java 1.7
switch(input) {
	case "Hello World" : 
		System.out.println("yep");
		break;
	default :
		System.out.println("uh");
		break;
}
System.out.println( "Hello World!" );

KieServices ks = KieServices.Factory.get();
KieContainer kContainer = ks.getKieClasspathContainer();
KieBase kieBase = kContainer.getKieBase();

for ( KiePackage kp : kieBase.getKiePackages() ) {
	for (Rule rule : kp.getRules()) {
		System.out.println("kp" + kp + " rule " + rule.getName());
	}
}

Console would log DRL compile fails with error:

Exception in thread "main" java.lang.RuntimeException: Error while creating KieBase[Message [id=1, level=ERROR, path=acme.drl, line=-1, column=0
   text=Error importing : 'defaultpkg.TheTest.theTest'], Message [id=2, level=ERROR, path=acme.drl, line=8, column=0
   text=[ function theTesttheTest (line:8): Cannot switch on a value of type String. Only convertible int values, strings or enum constants are permitted
 ]], Message [id=3, level=ERROR, path=acme.drl, line=1, column=0
   text=Rule Compilation error The import defaultpkg.TheTest cannot be resolved]]

Please notice the 'strings' bit in the error message : Cannot switch on a value of type String. Only convertible int values, strings or enum constants are permitted

Therefore would suggest it would compile a switch over String, but for some reason it is failing to recognize that input parameter is indeed a String?

Thank you
Ciao
MM