Redmine 1.1.1

I've created a set of tickets for a new project. In each issue I filled Subject, Description and Estimated time fields. I also filled blocks/blocked by dependencies in Related issues.

But the Gantt chart for this project is empty (that is, it contains all the tasks, but does not contain any "bars" for them).

I need to get a Gantt chart (or any other visual representation) to show to other project members.

I'd hate to type all that information again into OpenProj.

Is there a way to get a serviceable Gantt chart from the Redmine?

Update:

In the answers below I read that to get working Gantt chart I have to input start date and due date manually for each issue.

I believe that this information should be inferred automatically from start date of first ticket (first — depenency-wise), estimated time of each ticket, dependency graph, resource assignment and working hours calendar. Just as it happens in any minimally sane Gantt chart project management tool.

To enter this information by hand and to keep it up-to-date manually as the project evolves is insane waste of time.

Is there a way to generate Gantt chart from the set of Redmine tickets without filling in all this information manually? (Solutions involving data export + import in sane tool or involving existing plugins are perfectly acceptable.)