JCA BAPI Call Failures

The bit of code below works.  But exchange BAPI_PO_ITEMS for BAPI_PO_GETDETAIL and it fails.

function = this.createFunction("BAPI_PO_GETDETAIL");

if (function == null)

{

  System.out.println("Function" + " not found in SAP.");

  System.exit(1);

}

JCO.ParameterList input = function.getImportParameterList();

input.setValue("5000000021", "PURCHASEORDER");

mConnection.execute(function);

We get the error message:

com.sap.mw.jca.JCO$Exception: (104) RFC_ERROR_SYSTEM_FAILURE: The function module "BAPI_PO_GETITEMS" not released for 'remote' calls.

But it is!  Active, RFC enabled, and released. Works in SE37 called from another R/3 instance.

The only differences we see is that BAPI_PO_GETITEMS uses instance independent methods and has a mandetory table parameter.

We've tried it with other BAPIs and think it's always the instance independent ones with mandetory table parameters (but not 100% sure).