Getting the right StartDate for a planned work item

 I am working a TimeSheet_Details report in BIRT. It have on my report the Work Items (WIs) that have TimeSheet Entries (TSE) and also the parent WIs that do not have TSE´s (because you only submit actual time  spent for Tasks). The report still lacks the right Start Date for those planned work items. I was thinking about getting either the Planned StartDate (from the Planned Snapshot) or the ConstraintDate, which is filled after a succesful import from MS Excel in our case.