To Add physical MSG files to PST and generate PST we need to follow below steps:
  1. Add Com library Microsoft.Office.interop.outlook
  2. Create object of COM Object MailItem,Namespace,Application
  3. ns(object of namespace) = app(object of Applciation).GetNamespace("MAPI")

    ns.AddStoreEx(newPstFileLocation, OlStoreType.olStoreUnicode)
  4. For Each store As Store In ns.Session.Stores
    If store.FilePath = newPstFileLocation Then
    newPST = store
    End If
    Next
  5. Object of MAPI Folder Ex: oFolder
  6. oFolder = newPST.GetRootFolder
  7. .mail = CType(ns.Session.OpenSharedItem(filetobeprocessed), MailItem)

    mail.Move(folderInbox)

    folderInbox is object of Simple inbox folder and we are adding moving files to folderInbox.