Proper Case Conversion For Celtic Names

I've used this udf for a while with great success, but only on fields with more than one word....

http://weblogs.sqlteam.com/jeffs/archive/2007/03/09/60131.aspx

I'd like to know how I can adapt this function so it will convert a scottish/irish surname (McDonald or O'Shea) when there is only the surname in the column

This is what I'd been using for multiple words (Ronald McDonald). But it won't work on just Mcdonald. I'm sure it's just a simple tweak, but it all looks Punjabi to me?

Thanks in advance!!



CREATE FUNCTION [dbo].[f_ProperCase](@Text as varchar(512)) RETURNS varchar(512) as
BEGIN

DECLARE @Reset bit
DECLARE @Ret varchar(512)
DECLARE @i int
DECLARE @c char(1)

SELECT @Reset = 1, @i=1, @Ret = ''

WHILE @i <= LEN(@Text)
SELECT @c= SUBSTRING(@Text,@i,1),
@Ret = @Ret + CASE WHEN @Reset=1 THEN UPPER(@c) ELSE LOWER(@c) END,
@Reset= CASE WHEN
CASE WHEN SUBSTRING(@Text,@i-4,5) like '_[a-z] [DOL]''' THEN 1
WHEN SUBSTRING(@Text,@i-4,5) like '_[a-z] [D][I]' THEN 1
WHEN SUBSTRING(@Text,@i-4,5) like '_[a-z] [M][C]' THEN 1
ELSE 0
END = 1
THEN 1
ELSE CASE WHEN @c like '[a-zA-Z]' or @c in ('''') THEN 0
ELSE 1
END
END,
@i = @i +1
RETURN @Ret

-- Test: SELECT dbo.f_ProperCase('it''s crazy! i couldn''t believe kate mcdonald, leo dicaprio, (terrence) trent d''arby (circa the 80''s), and jada pinkett-smith all showed up to [cHris o''donnell''s] party...donning l''oreal lIpstick! They''re heading to o''neil''s pub later on t''nite. the_underscore_test. the-hyphen-test.' )
END