Duration only - not scheduled

[Ipim19]

How can I set a duration for a Task and not specify a date/time?

Example:
When making a small list of tasks it is sometimes cumbersome to schedule everything.
But still a basic timing is needed to get a feeling for the upcoming tasks.
This can be done by giving tasks a estimation like >>>Task 1 - 10 minutes, Task 2 - 5 Minutes, Task 3 - 2 hours... etc.

How can I do this in Epim?
It seems to me that the Duration is not directly editable and is only visible after scheduling a task. Is this correct?
If yes... please add this feature - it is quite useful.

EDIT: I am used to do it like this from another program. There this feature it is called "planning". So there is planning vs. scheduling, where a planned task is given an amount of time and it can be done at any time during a day. And a scheduled task has to be done during a specified time - the way it is right now in Epim.
I actually thought I could do this by assigning the task to a day... but when I do this, the duration is set to 1 day and the value is not editable. (at least I did not find a way to do it. )

[admin]

There is currently no such option available. We will consider implementing it in the future.

[aurio]

I could also imagine that this would be a useful option for some purposes