Sub-Task should have independent security levels

When creating a sub-task, it automatically inherits the security
level of its parent. Using the workaround described in JRA-5442,
it is possible to change the security level of the sub-task, e.g.
to hide special tasks from your customers.

However, it is not possible to set the ("hidden") security level
upon creation of the sub-task. So, if you want to create a
private sub-task, that is not accessible by your customers, you have
to first create a sub-task that is automatically private, hence
generating an automatic eMail notification of your customer. Then,
you have to edit the sub-task to change the security level.

Wouldn't it be more efficient to let the user choose the security level
when creating the sub-task?
Or could we have special security levels for different types of sub-tasks.
E.g. create a sub-task "private sub-task" that automatically relates to
a certain security level "private".

(Just to explain: We are using Jira Enterprise 3.0.3 to track new
features. It is used by us and our clients. When a new feature issue is
created, we put several development/private sub-tasks under it, to
split work for one feature or to assign private work that has to
be done in order to build the new feature. But we do not want our
customer to see, what is going on "behind the scenes".)