I don't believe there is a way to pass extra parameters down into the HBase connection factory when running on the GraphComputer. It looks like ext parameters should be captured like they are in OLTP mode when under the storage namespace and passed through. This causes an issue right now with Bigtable because there isn't a way to pass the Bigtable specific parameters including google.bigtable.project.id, google.bigtable.instance.id, and hbase.client.connection.impl.