Write your own function - this one should do the job:
Code:
Function McStrConv(expr As Variant) As String
Dim ThirdChar As String
McStrConv = StrConv(expr, 3)
If Left(McStrConv, 2) = "Mc" And Len(McStrConv) > 2 Then
ThirdChar = UCase(Mid(McStrConv, 3, 1))
McStrConv = "Mc" & ThirdChar & Right(McStrConv, Len(McStrConv) - 3)
End If
End Function