So how do you want the to appear in GCal? As all-day tasks?
Anyway, I have tried some before. (search gcal start date)
Posted by Folke X:
Here are the results:
Task 1: Start 2 pm, Due 4 pm
shows in GCal as an event 2 pm - 4 pm
Task 2: Due 2 pm, Length 2 hrs
shows in GCal as an event 12 pm - 2 pm
Task 3: Start 2 pm, Length 2 hrs
shows in GCal as an event 2 pm - 4 pm
For the tasks using due date/time I used the default setting "due by" (there are three other optional settings available)
I also have some tasks of my own that are encoded as due at 11 pm (nothing else; no start; no length). These show in GCal as events 11 pm - 11 pm in the numerical event info, but as a half hour block in the visual "day" diagram.
Notice the last section above!