动态发送端口 - BizTalk

Saludos，

我正在尝试在业务流程中构建动态发送端口，但出现以下错误

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属性"出站传输位置"具有长度值 大于 256 个字符">

MessageOut = MessageIn;
jsonMessage = {"id":0,"original":"1","tipoId":"610","comments":"BizTalk","privadoNotes":null,"PriodidadyValue":null,"cityId":"1","streetNum":null,"streetId":"0","crossStreetId":"0","latitude":"0","longitude":"0"}
InitialUri = System.String.Format("http://ThisIsaURLTheRealOneAndBig.com/someplace/api/v1/requests/add/?key=5dd5d45d4sdd54dds5s54s5s45s4s5s4s545s4swws&request={0}", jsonMessage);
System.Diagnostics.EventLog.WriteEntry("Orchestration Debug", System.String.Format("The Value = {0}", InitialUri));
MessageOut(WCF.BindingType)="WsHttpBinding";
DynamicsTOSend(Microsoft.XLANGs.BaseTypes.Address) = InitialUri; //this URI Finally is bigger than 256
DynamicsTOsend(Microsoft.XLANGs.BaseTypes.TransportType) = "HTTP"; 

请问有什么想法吗？