You'll be able to create such a keyspace, if you first update your Cassandra configuration. You have to update cassandra-topology.properties
in your node configuration, to tell either a default settings or describe you data centers and racks. The default content of the file is self explanatory.
After that is setup properly, you can properly create your keyspace. But it is better to follow the advice of jbellis, to not create the keyspace from code.