Custom Workflow activity/Plugin to send Email to a recipient not in CRM

		Guid fromID = context.UserId;
		Entity sendEmail = new Entity("email");

		Entity fromReciepent = new Entity("activityparty");
		fromReciepent["partyid"] = new EntityReference("systemuser", fromID); //gets the look up

		sendEmail["subject"] = emailSubject;
		sendEmail["from"] = new Entity[] { fromReciepent }; // this works
		sendEmail["description"] = fullhtml;
		sendEmail["bcc"] = "test@yahoo.com ";  // This does not work,
		sendEmail["to"] = new Entity[] { fromReciepent }; //this works



		Guid emailID = service.Create(sendEmail);

		SendEmailRequest reqSendEmail = new SendEmailRequest();
		reqSendEmail.EmailId = emailID;
		reqSendEmail.IssueSend = true;
		reqSendEmail.TrackingToken = "";
		service.Execute(reqSendEmail);