How to set file properties for Excel file in VB6

'==========================================================================
' Tutorial 33
'
' This tutorial shows how to set document properties for Excel file in VB6,
' like 'Subject' property for summary information, 'Manager' property for
' document summary information and a custom property.
'==========================================================================

VERSION 5.00
Begin VB.Form Form1 
    Caption         =   "Form1"
    ClientHeight    =   4590
    ClientLeft      =   60
    ClientTop       =   345
    ClientWidth     =   6885
    LinkTopic       =   "Form1"
    ScaleHeight     =   4590
    ScaleWidth      =   6885
    StartUpPosition =   3  'Windows Default
    Begin VB.Label Label1 
        AutoSize        =   -1  'True
        Height          =   100
        Left            =   120
        TabIndex        =   0
        Top             =   120
        Width           =   100
    End
End

Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False

Private Sub Form_Load()

    FileProperty.Initialize

    Me.Label1.Caption = "Tutorial 33" & vbCrLf & "-----------------" & vbCrLf

    ' Create an instance of the class that exports Excel files
    Set workbook = CreateObject("EasyXLS.ExcelDocument")

    ' Create a worksheet
    workbook.easy_addWorksheet_2("Sheet1")

    ' Set the 'Subject' document property
    workbook.getSummaryInformation().setSubject("This is the subject")

    ' Set the 'Manager' document property
    workbook.getDocumentSummaryInformation().setManager("This is the manager")

    ' Set a custom document property
    workbook.getDocumentSummaryInformation().setCustomProperty "PropertyName", VT_NUMBER, "4"

    ' Export Excel file
    Me.Label1.Caption = Me.Label1.Caption & vbCrLf & _
                           "Writing file C:\Samples\Tutorial33 - Excel file properties.xlsx"
    workbook.easy_WriteXLSXFile ("C:\Samples\Tutorial33 - Excel file properties.xlsx")

    ' Confirm export of Excel file
    If workbook.easy_getError() = "" Then
        Me.Label1.Caption = Me.Label1.Caption & vbCrLf & "File successfully created."
    Else
        Me.Label1.Caption = Me.Label1.Caption & vbCrLf & "Error: " & workbook.easy_getError()
    End If

    ' Dispose memory
    workbook.Dispose
End Sub