Private Sub Document_DocumentOpened(ByVal doc As IVDocument)
    CbrInit 'создание кнопки на панели инструментов
End Sub

Sub CbrInit()
    Set cbrCommandBars = Visio.Application.CommandBars
    On Error Resume Next
    Err.Clear
    Set cbrCommandBar = cbrCommandBars("My_Toolbar")
    If Err.Number = 0 Then Exit Sub 'если тулбар уже создан, то выход
    Set cbrCommandBar = cbrCommandBars.add(Name:="My_Toolbar", _
        Position:=msoBarTop, Temporary:=False)
    cbrCommandBar.Protection = msoBarNoCustomize
    cbrCommandBar.Visible = True
    Set cbbCommandBarButton = cbrCommandBar.Controls.add(Type:=msoControlButton)
    With cbbCommandBarButton
        .Caption = "мой код"
        .TooltipText = "Запуск"
        .tag = "мой код"
        .FaceID = 59
        .OnAction = "ThisDocument.Main"
    End With
End Sub

Sub Main()
   здесь код твоей программы
End Sub