Scrum Board does not show sum of Estimated Hours when Stories have sub-tasks

We are using rapid board (SCRUM option) to control our sprints.

Instead of using story points, we've decided to use original estimate as the base (effort) for our burndown. However, the original estimate is not directly defined on the stories. Instead of that, we detail our stories in subtasks, we inform the original estimate (effort) for all the subtasks and, after that, JIRA just INDIRECTLY accumulates the sum of its subtasks as the story's original estimate.

The problem is (please see screenshots attached):

• Scrum Board (Plan mode) does not show the sum of estimated hours on the respective spot.
• Due that, Scrum Board (Report mode) - Velocity Chart - also does not show the chart with the information registered. The bar chart demonstrates no information, because it does not recognize the amount of hours (remaining / registered) on subtasks.

After a quick test, I've discovered:

• The features mentioned above ONLY WORKS if the hour estimates (original time estimate) were informed DIRECTLY on the stories. It means, a story WITH NO subtasks.

In short, this situation does not fit for us. We really need to decompose our stories in subtasks and, after that, simply let the scrum rapid board (no matter the mode [plan | work | report]) do its job.

Finally, if you need more information, please just let a comment.

Thanks!