Create a custom SQL Server function to convert a string to Proper Case

I have been using a Visual Basic function for years that takes the customer and company names submitted by my sales people and converts the names to Proper Case.? Many people type using all lower case or all UPPER CASE a I don't think that always looks professional.? The function does more than just use the VB StrConv function to capitalize the first letter of each word.? It also needs to handle exceptions like McDonald, MacDonald, and others.? The VB code is attached.? I would like it converted to an SQL function.? Your own improvements would also be appreciated.