you can use the iCal feed to add your Todoist tasks to any calendar software that supports this standard. The feed can be found in Preferences -> General Settings.
Unfortunately, if won't set up other non-Todoist reminders within the calendar software, though. Sorry for the inconvenience.
I have now created a subscription to my ical and I can view the tasks that include in a reminder! Now, how can I view these tasks on my blackberry is that possible?