‘Access is denied’ msg with Quest ActiveRoles 7.1 Management Shell

My customer asked me to create scheduled task uses cmdlets from Quest ActiveRoles 7.1 Management Shell. Missing documentation caused my long fight with ‘Access is denied’ monster.

Fully Qualified Error ID = System.UnauthorizedAccessException,Quest.ActiveRoles.ArsPowerShellSnapIn.Commands.RemoveGroupMemberCmdlet2

System.UnauthorizedAccessException: Access is denied.
at System.DirectoryServices.Interop.UnsafeNativeMethods.IAds.SetInfo()
at System.DirectoryServices.DirectoryEntry.CommitChanges()
at Quest.ActiveRoles.ArsPowerShellSnapIn.DirectoryAccess.AdsiDirectoryObject.SetInfo()
at Quest.ActiveRoles.ArsPowerShellSnapIn.BusinessLogic.ObjectCache.Save(IEnumerable`1 controls)
at Quest.ActiveRoles.ArsPowerShellSnapIn.Commands.RemoveGroupMemberCmdlet2.ProcessRecord()
at System.Management.Automation.CommandProcessor.ProcessRecord()

But solution is easy, you have to use this cmdlet

Connect-QADService -Service "quest_server.fqdn" -Proxy