Question : SEND AS Permissions problem

Hi all.
My problem has three parts:
First one:
When trying to assign permissions for any one member of any protected
Group the “send as” in order to be able to send  as a group on exchange 2010 , they keep say:
Active Directory operation failed on DOM-CONTROLLER. This error is not retriable. Additional information: Access is denied. Active directory response: 00000005: SecErr: DSID-031521D0, problem 4003 (INSUFF_ACCESS_RIGHTS), data 0 the user has insufficient access rights.
I read this article but it did not solve my problem:  http://msexchangeteam.com/archive/2009/09/23/452595.aspx
Second part:
For any normal user, after successfully assign the permissions to send as a group, sometimes it works and sometimes
Not, does it matter of time? Is for any one member of any protected
Group there any service may I restart in order action takes effects.
I receive this error on OWA:
You don't have the permissions required to send messages from this mailbox.

Third Part:
In exchange 2010 do am still have to tick the send as permission for any user or group on the ACL for the same user or group?

Regards

Answer : SEND AS Permissions problem

No you do not need a CAL for this.
Is the mailbox that you are sending as still a member of a protected group in AD?
If yes, send as permissions will be reset at random intervals and cannot be changed as long as the user is a member of the protected group.