BackgroundColorClassName only support All/Full Day event?

Hello

I have created a calendar web part. I am trying to give different colors to the events in SPCalendarView  available with Sharepoint 2007. I am trying following code

SPCalendarItem item = new SPCalendarItem();
item.BackgroundColorClassName = "ms-calendar-mycolorclass";

I have added the different color tag  class in calendar.css to make it work.

This functionality works only for full day events. When an event is  partial day event thne it wont take the color. P

Any ideas, how can this be achieved or any better idea to implement this?