DataSource grouping by NSDate

I didn't see a specific section for TKDataSource so I'll just put this here for now. I'm trying to use the TKDataSource to group various items by a date, and the grouping works but it's not filtered in ascending/descending order and even if I add a sort option it doesn't take it. A second issue is if I use the TKDataSource as a UITableView datasource is there a way to update the text used as the grouping key (again I'm using a NSDate, but it prints the full date and I would want to use a shorter date string for the section header).