That's what I initially tried, it doesn't like if you change the standard autocalendar script. I ended up just copying the script out and making my own calendar with the values week/end, month/end ect.. was the easiest way to do it. You then end up with 2 autoscripted sections for some reason but it works
I hardly ever use the data manager so I just unlocked the Auto-generated section and updated the script. We control the data model from outside the app so I wrote a function that looks for fields flagged as dates and then it builds the auto calendar for those fields. This allows me to add things such as days ago in the auto calendar as well.