Then I was confronted with another problem. The previous calendar starts on Sunday and this one on Monday. Users got confused and selects one day ahead (dump people!!!). I had to fix it.
So I went ahead and looked into the code. I was thinking its going to be a night mare. But just a small change and commenting two lines made it work.
If you have the same problem find the following and comment it.
//Changed Calendar to start on Sunday
//if(dayStartOfMonth==0)dayStartOfMonth=7;
//dayStartOfMonth--;
Change the day array to have 'Sun' first, for the language you are using. i.e. var dayArray = ['Sun','Mon','Tue','Wed','Thu','Fri','Sat'];