Unable to provision an AWS SQL Server RDS instance in Multi AZ using boto

I'm trying to provision an SQL Server Standard Edition AWS RDS instance which is mirrored across two AZs using boto's rds2.

Whenever I call the create_db_instance method in boto.rds2.layer1.RDSConnection with the appropriate arguments, I keep getting the following error:

boto.exception.JSONResponseError: JSONResponseError: 400 Bad Request
{'RequestId': 'fdc54b48-0586-11e5-951d-c3153310155b', 'Error': {'Message': 'To configure Multi-AZ for SQL Server DB Instances please apply or remove the "Mirroring" option using Option Groups.', 'Code': 'InvalidParameterCombination', 'Type': 'Sender'}}

I've verified that I'm setting the option multi_az = True and the option_group_name is set to an option group which has mirroring enabled. Here's my call to create_db_instance. Are there any other settings which need to be set before I can provision this RDS instance which is mirrored?

conn.create_db_instance(db_instance_identifier=new_db_name,
                                    allocated_storage=allocated_storage,
                                    db_instance_class=rds_instance_class,
                                    master_username=master_username,
                                    master_user_password=master_password,
                                    port=port,
                                    engine=rds_engine,
                                    multi_az=rds_multi_az,
                                    auto_minor_version_upgrade=auto_minor_version_upgrade,
                                    db_subnet_group_name=rds_subnet_group,
                                    license_model=license_model,
                                    iops=iops,
                                    vpc_security_group_ids=rds_vpc_security_group,
                                    option_group_name=option_group_name
                                )

I'm also seeing another issue where I can either provision with IOPS or provision with Magnetic disks when I remove the iops option. But, I haven't figured out a way to provision with just General Purpose SSDs.