Igor, I guess you went through the config guide and it says there when the "bandwidth remaining" command becomes available in the config for the class. Also you can try police xx command in the class for priority traffic Hope this helps.
config will look something like this:
policy-map Policy-1
class VOICE-BEARER
priority
police conform-action transmit
Priority queuing
On Supervisor Engine 6-E only one transmit queue on a port can be configured as strict priority (termed Low Latency Queue, or LLQ).
LLQ provides strict-priority queuing for a traffic class. It enables delay-sensitive data, such as voice, to be sent before packets in other queues. The priority queue is serviced first until it is empty or until it is under its shape rate. Only one traffic stream can be destined for the priority queue per class-level policy. You enable the priority queue for a traffic class with the priority policy-map class configuration command at the class mode.
A LLQ can starve other queues unless it is rate limited. Supervisor Engine 6-E does not support conditional policing where a 2-parameter policer (rate, burst) becomes effective when the queue is congested (based on queue length). However, it supports application of an unconditional policer to rate limit packets enqueued to the strict priority queue.
When a priority queue is configured on one class of a policy map, only bandwidth remaining is accepted on other classes, guaranteeing a minimum bandwidth for other classes from the remaining bandwidth of what is left after using the priority queue. When a priority queue is configured with a policer, then either bandwidth or bandwidth remaining is accepted on other classes.
