Call SendingService.SendNewsletter
Send an email campaign or a newsletter to one or more lists. This method can also be used to send SMS to a list. The following date format is valid: yyyyMMddTHHmmss. Optional to include a CampaignId. This Id will be available shortly in API methods related to send-outs (i.e. it can currently not be retrieved using the API). This method returns a SendQueueId in response to a successful call.