Word bookmark refinement

A previous answer gave me this piece of code to replace every instance of a given text with a sequentially numbered set of bookmarks.  This works if rng.Text = "" 
However I want replace the text XXX with the word DATA (inside the new bookmark) but if I change
rng.Text = "" 
to
rng.Text = "DATA"
then I only get one bookmark and the other instances of XXX are ignored. What should I be doing?


Sub ReplaceWithBookmarks()
    Dim rng As Range
    Dim iBookmarkSuffix As Integer
    Dim strBookMarkPrefix
   
    strBookMarkPrefix = "BM"
   
    Set rng = ActiveDocument.Range
    With rng.Find
        .Text = "XXX"
        Do While .Execute
            rng.Text = "" 'clear the "XXX" (optional)
            iBookmarkSuffix = iBookmarkSuffix + 1
            ActiveDocument.Bookmarks.Add strBookMarkPrefix & iBookmarkSuffix, rng
        Loop
    End With
End Sub

The second related issue is that I do not want to lose the bookmarks when I put replacement text into them. The code below puts in the text but I lose the bookmark.

For Each MyBook In ActiveDocument.Bookmarks
    sbook = UCase(Left(MyBook.Name, 2))
    Select Case sbook
        Case "BM"
            MyBook.Select
            MyBook.Range.Text = "his"
    End Select
Next

I want to keep the bookmark with the word "his" inside it

I found a cumbersome solution adding another bookmark then later renaming it back to the original but I am sure there is a simpler way?