Availability zone ignored in ec2 api

The ec2 api parameter incorrectly parsed in api. When i use euca-run-instance with -z myzone, nova ignore this flag and start instance on random chosen host. In logs i can see that api receives that parameter:

2011-11-11 14:57:26,566 DEBUG nova.api [-] arg: Placement.AvailabilityZone val: twinB from (pid=2221) __call__ /usr/lib/pymodul
es/python2.6/nova/api/ec2/__init__.py:241

But then this value is thrown away and instance have started on host 'server-118'.
I suppose there is a mistake in nova/api/ec2/cloud.py in method run_instances:

        instances = self.compute_api.create(context,
            instance_type=instance_types.get_instance_type_by_name(
                kwargs.get('instance_type', None)),
            image_href=self._get_image(context, kwargs['image_id'])['id'],
            min_count=int(kwargs.get('min_count', max_count)),
            max_count=max_count,
            kernel_id=kwargs.get('kernel_id'),
            ramdisk_id=kwargs.get('ramdisk_id'),
            display_name=kwargs.get('display_name'),
            display_description=kwargs.get('display_description'),
            key_name=kwargs.get('key_name'),
            user_data=kwargs.get('user_data'),
            security_group=kwargs.get('security_group'),
            availability_zone=kwargs.get('placement', {}).get(
                                  'AvailabilityZone'),
            block_device_mapping=kwargs.get('block_device_mapping', {}))

While all parameters, retreived from ec2 have lowercase and underscore-delimeted key in kwargs dict, availability_zone still use CamelCase. When i changed this piece of code with this:

        instances = self.compute_api.create(context,
            instance_type=instance_types.get_instance_type_by_name(
                kwargs.get('instance_type', None)),
            image_href=self._get_image(context, kwargs['image_id'])['id'],
            min_count=int(kwargs.get('min_count', max_count)),
            max_count=max_count,
            kernel_id=kwargs.get('kernel_id'),
            ramdisk_id=kwargs.get('ramdisk_id'),
            display_name=kwargs.get('display_name'),
            display_description=kwargs.get('display_description'),
            key_name=kwargs.get('key_name'),
            user_data=kwargs.get('user_data'),
            security_group=kwargs.get('security_group'),
            availability_zone=kwargs.get('placement', {}).get(
                                  'availability_zone'),
            block_device_mapping=kwargs.get('block_device_mapping', {}))

all works fine.