Question about tweaking Vanilla file which generates calendar

In a nutshell, I'm trying to adjust the format which these files

• /app/calendar/calendar.r
• /app/calendar/lib.core.r
• /app/calendar/month-line.r
• /app/du-jour/calendar-core.r
• /app/du-jour/calendar-month-line.r
• /app/du-jour/calendar.r

generate. The reason is because the normal monthly calendar in these parts start their week on Sunday. Weird, I know. I'm patiently waiting for an extra weekday to be invented by the Pope.

y!kes