async def METHOD_NAME(
    self, campaign_id: str, messaging_service_sid: str
) -> ExternalCampaignInstance:
    """
    Asynchronously create the ExternalCampaignInstance
    :param campaign_id: ID of the preregistered campaign.
    :param messaging_service_sid: The SID of the [Messaging Service](https://www.twilio.com/docs/messaging/services/api) that the resource is associated with.
    :returns: The created ExternalCampaignInstance
    """
    data = values.of(
        {
            "CampaignId": campaign_id,
            "MessagingServiceSid": messaging_service_sid,
        }
    )
    payload = await self._version.METHOD_NAME(
        method="POST",
        uri=self._uri,
        data=data,
    )
    return ExternalCampaignInstance(self._version, payload)