WebDateChooser control not supporting th-TH culture

When i load the WebDateChooser control for first time, its working fine but as i select the date the value change event will fire after that date is displaying as 12/12/2555 instead of 12/12/2012

 System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat.Calendar = New System.Globalization.GregorianCalendar()

By using above code i changed datetime format as GregorianCalendar format.

Please find the screen shot