The problem is that the provider model wrapped around it doesn't support all of the features of the jsCalendar. To do that you will need to not use our <mp:DatePicker, but instead use <mp:jsCalendarDatePicker which is a direct wrapper around the jsCalendar javascript. Then you can set the Theme property on the control so something like this:
<mp:jsCalendarDatePicker id="cal1" runat="server" Theme="CalendarMojo" ShowTime="true" />
valid options for theme are:
CalendarMojo,
CalendarBlue,
CalendarBlue2,
CalendarBrown,
CalendarGreen,
CalendarWin2k1,
CalendarWin2k2,
CalendarWin2kCold1,
CalendarWin2kCold2,
CalendarSystem,
CalendarTas
CalendarMojo, CalendarBlue, CalendarBlue2, CalendarBrown, CalendarGreen, CalendarWin2k1, CalendarWin2k2, CalendarWin2kCold1, CalendarWin2kCold2, CalendarSystem, CalendarTas
Hope it helps,
Joe