procedure TForm1.Button1Click(Sender: TObject);
var ws:SmevUnifoService ;
    mes:message_;
    mesdata:messagedata;
    s:sender_;
   
begin

s.Code:='1ххх2';
s.Name_:='БАНК';
mes.Recipient.Code:='1111';
mes.Recipient.Name_:='СМЭВ';
mes.TypeCode:=TypeCodeType(0);
mes.Status:=StatusType(0);
//mes.Date_.AsDateTime:=sysutils.Date ;
mes.ExchangeType:='хз';

mes:=message_.Create;
mesdata:=messagedata.Create;

//получаем интерфейс
ws:=GetSmevUnifoService(false,'',HTTPRIO2 );
//вызываем процедуру

ws.UnifoTransferMsg(mes,mesdata);

end;

<?xml version="1.0"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <SOAP-ENV:Body>
      <UnifoTransferMsg xmlns="http://roskazna.ru/SmevUnifoService/">
         <Message xmlns="http://smev.gosuslugi.ru/rev111111">
           <Sender_ xmlns="" xsi:nil="true"/>
           <Recipient xmlns="" xsi:nil="true"/>
           <TypeCode>GSRV</TypeCode>
           <Status>REQUEST</Status>
           <Date_ xmlns="" xsi:nil="true"/>
           <ExchangeType></ExchangeType>
        </Message>
        <MessageData xmlns="http://smev.gosuslugi.ru/rev111111"/>
     </UnifoTransferMsg>
  </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

procedure TForm1.HTTPRIO2AfterExecute(const MethodName: String;
  SOAPResponse: TStream);
var
  Temp: TStringStream;
begin
Temp := TStringStream.Create('');

    Temp.CopyFrom(SOAPResponse, 0);
    Memo2.Text := Temp.DataString;

    Temp.Free;

end;

procedure TForm1.HTTPRIO2BeforeExecute(const MethodName: string;
  SOAPRequest: TStream);
var
  Temp: TStringStream;
begin
Temp := TStringStream.Create('');

    Temp.CopyFrom(SOAPRequest, 0);
    Memo1.Text := Temp.DataString;

    Temp.Free;

end;

procedure TForm1.Button1Click(Sender: TObject);
var ws:SmevUnifoService ;
    mes:message_;
    mesdata:messagedata;
    SB:array of SupplierBillID2;
begin

mes:=message_.Create;
mesdata:=messagedata.Create;

mes.Sender:=smevunifoservice1.sender.Create;
mes.Sender.Code :='1ххх2';
mes.Sender.Name_:='БАНК';

mes.Recipient:=recipient.Create;
mes.Recipient.code:='RKZN35001';
mes.Recipient.Name_:='Казначейство России';


mes.TypeCode:=TypeCodeType(0);
mes.Status:=StatusType(0);
mes.Date_:=Date_.Create;
mes.Date_.AsDateTime:=Date ;
mes.ExchangeType:='0';

mesdata.AppData:=AppData.Create;
mesdata.AppData.exportData:=exportData.Create;
mesdata.AppData.exportData.DataRequest:=Datarequest.Create;
mesdata.AppData.exportData.DataRequest.PostBlock:=PostBlock.Create;

mesdata.AppData.exportData.DataRequest.PostBlock.ID:='7ba91a04-9f25-463e-8227-ca3e46354c43';
//mesdata.AppData.exportData.DataRequest.PostBlock.TimeStamp.AsUTCDateTime:=now;  Теперь ошибка здесь!!!
mesdata.AppData.exportData.DataRequest.PostBlock.SenderIdentifier:='1234ABC123';

setlength(SB,1);
SB[0]:='18800000000001786439';
//mesdata.AppData.exportData.DataRequest.SupplierBillIDs:=SB[0]; и вот здесь!!!

//получаем интерфейс
ws:=GetSmevUnifoService(false,'',HTTPRIO2 );
//вызываем процедуру
ws.UnifoTransferMsg(mes,mesdata);


end;

 // ************************************************************************ //
  // XML      : PostBlock, global, <complexType>
  // Namespace : http://roskazna.ru/xsd/PostBlock
  // ************************************************************************ //
  PostBlock = class(TRemotable)
  private
    FID: ID;
    FTimeStamp: TXSDateTime;
    FSenderIdentifier: string;
  public
    destructor Destroy; override;
  published
    property ID:              ID          Index (IS_UNQL) read FID write FID;
    property TimeStamp:        TXSDateTime  Index (IS_UNQL) read FTimeStamp write FTimeStamp;
    property SenderIdentifier: string      Index (IS_UNQL) read FSenderIdentifier write FSenderIdentifier;
  end;

DataRequest2 = class(RequestTemplate)
...
property SupplierBillIDs: SupplierBillIDs  Index (IS_OPTN or IS_UNQL) read FSupplierBillIDs write SetSupplierBillIDs stored SupplierBillIDs_Specified;

SupplierBillID2 =  type string;      { "http://roskazna.ru/xsd/PGU_DataRequest"[Smpl] }
  SupplierBillIDs = array of SupplierBillID2;  { "http://roskazna.ru/xsd/PGU_DataRequest"[Cplx] }

mesdata.AppData.exportData.DataRequest.PostBlock.TimeStamp:=Timestamp.Create;

mesdata.AppData.exportData.DataRequest.PostBlock.TimeStamp.Create;

mesdata.AppData.exportData.DataRequest.SupplierBillIDs:=SB;

mesdata.AppData.exportData.DataRequest.PostBlock.TimeStamp.AsUTCDateTime:=now;  

var dt:TXSDateTime;

...

dt:=TXSDateTime.create;
dt.asDateTime:=now;
mesdata.AppData.exportData.DataRequest.PostBlock.TimeStamp.AsUTCDateTime:=dt;