The store is only supported in server mode, and it's supposed to be deployed as a custom cache store. Custom cache stores can only be configured with properties, like this

<store name="customStore" class="org.infinispan.persistence.cassandra.CassandraStore">
    <property name="keyspace">keyspace</property>
    <property name="servers">localhost:1111;localhost:2222</property>
</store>

To do this, the CassandraStoreConfigurationBuilder needs to accept all the configuration options also in String format.