I am using a Macro Public Function in Excel which format the date:

Optional Formato As String = "dd mmmm yyyy" _
                       ) As Variant

this display by example 11 Febrero 2008,
but I need to display     11 de Febrero de 2008

It's possible to change to this format?

Thanks for your help

Complete Macro:
Public Function FechaSi( _
 Optional Condicion As Variant = "", _
 Optional SiCumple As Variant = "", _
 Optional SiNoCumple As Variant = "", _
 Optional Formato As String = "dd mmmm yyyy" _
                       ) As Variant
 If Condicion = "" Or Condicion = True Then
   If SiCumple = "" Then
     SiCumple = Format(Now, Formato)
   ElseIf IsDate(SiCumple) Then
     SiCumple = Format(CLng(CDate(SiCumple)), Formato)
   End If
   FechaSi = SiCumple
 Else
   If IsDate(SiNoCumple) Then SiNoCumple = _
     Format(CLng(CDate(SiNoCumple)), Formato)
   FechaSi = SiNoCumple
 End If
End Function