There is one major difference between ACT! and Outlook in the arena of Tasks and Todo's. While in Todo's you can specify the due time and then a reminder (lead time) when the task should be started, however, in Outlook, you can only specify the Start Date and then the reminder time to start the task. In Outlook, there is no "lead time" to execute tasks.
ACT-Outlook Synchronizer deals with this dichotomy by mapping the ACT! Start Time less the lead time as the reminder time in Outlook.
If in Outlook, the Reminder is set to a date AFTER the start of the task, the lead time in ACT! is set to 0. It the reminder is set to a time before the start date, the difference between the start date and the reminder date becomes the lead time in ACT!.