GreenHopper assumes that 5 days a week means Monday to Friday

The JIRA timetracking feature allows to specify how many days per week are work days, and I have it set to 5 days.
In Israel, 5 days work week starts on Sunday and ends on Thursday, unlike most countries where Sunday is the day off.

When looking at GreenHopper burn down charts - the non-working days are automatically set to Saturday and Sunday, and it's just plain wrong.
I could not find any way to make GH think otherwise.

Would be nice if there was a configuration item where first day of the week can be chosen, either Sunday or Monday.