Public Function ReplaceChars(Source As String, Char As String, MaxChars As _
  Long) As String
'// Ersetzt mehrfaches <Char> in <Source>
 
Dim i As Long
Dim nCount As Long
i = 1
 
For i = 1 To Len(Source)
      If Mid$(Source, i, 1) = Char Then
            nCount = nCount + 1
 
            If nCount > MaxChars Then
                ' Zeichen aus String entfernen
                Mid$(Source, i, 1) = Chr$(1)
            End If
      End If
Next i
 
ReplaceChars = Replace(Source, Chr$(1), "")
End Function

Dim s As String, c As String
s = "bla....bla...bla....bla....."
c = "."
MsgBox ReplaceChars(s, c, 2)