The problem with creating traffic shaping on srx 240 h2.

Hi.
I have Juniper srx240h2. I want to create traffic shaping on untrust external interface ge-1/0/0 unit 75. On that interface i have 4 vlan's. I was creating filter, schedulers and scheduler-map. When i was trying to apply scheduler-map to external interface:
class-of-service {
    interfaces {
        ge-1/0/0 {
            unit 75 {
                scheduler-map my-scheduler-map;
            }
         }
     }
}
I received error:
1) 'per-unit-scheduler', 'hierarchical-scheduler', or 'shared-scheduler' for this interface is required for scheduler map on interface unit
I will be glad of any help.