duration issue

The duration of a day is assumed to 8 hours. Is there any way to change this ? My requirement is 1 day = 24 hours. Or can I specify the start and finish date for a task without the duration in hours?

In the current version you can only change it manually in the source code, the line
this.hoursInDay = 8;

we have new method ganttChartControl.setHoursInDay(24) coming with the next version (planned for March 9th)