Wedding

I am getting married November 21, 2015 and everything else is going smoothly, all except for one problem...my sister. I, honestly, do not want her in my wedding. She is very disrespectful to me and is very cruel and mean. She does not listen to me and is just out and out not my favorite. My parents, of course, want her and my other sister in the wedding but I really don't her in it because of how she treats and has no respect for me what so ever. I honestly do not care if her feelings will be hurt because she does not deserve to be apart of my day if she doesn't know how to respect. My parents however defend her and spoil her because she is "the baby", but that does not give her the right to be disrespectful to me and I do not have to deal with it, so I am putting my foot down with this. How would I go about telling them I do not want her apart of my wedding?