URL    = "https://b24-ar17wx.bitrix24.by/rest/1/yg2...";
    TaskID = "3832";
    FileID = "20820";

    Result = OPI_Bitrix24.AttachFileToTopic(URL, TaskID, FileID);

    URL    = "b24-ar17wx.bitrix24.by";
    Token  = "f3925167006e9f06006b12e400000001000...";
    TaskID = "3834";

    Result = OPI_Bitrix24.AttachFileToTopic(URL, TaskID, FileID, Token);