Sending a message to a service endpoint from an adapter

How can I send a message to a service endpoint from an adapter? I've created a custom adapter to integrate with our CMS. I need to send messages to a topic associated with a service endpoint, following certain actions.

I tried the following:

this.RaiseReceiveFromEndpointEvent(notificationRequestMessage, null)

The "notificationRequestMessage" object is an ESBMessage whose body is a data contract object. This object is consumed by a WCF service that sends emails:

[OperationContract(Name = "SendNotification", Action = "Notification\SendNotification")]
public SendNotificationResponse SendNotification(NotificationRequest request)

The issue I'm experiencing is that the WCF service is failing with the following error:

"OperationFormatter encountered an invalid Message body. Expected to find node type 'Element' with name 'SendNotification' and namespace 'ns'. Found node type 'Element' with name 'NotificationRequest' and namespace 'ns'"

What is the recommended method of sending a message to a service endpoint that is expecting a SOAP message?