MPLS and NV2 QoS

Hi Guys, i need some help. I understand that NV2 QoS could classify packet in order to the EXP-Bit in the MPLS labels.

R1= has the VPLS bridged with backbone interface
R4= has the VPLS bridged with clients interface

R1-R2-R3-R4 are a full OSPF/MPLS netowork with TE configured in each end only used for path selection

R1 ---------------------- R2 ------wireless------ R3 ----------------------R4


I need to set in R1 and R4 packet priority to MPLS Exp-bit (i don’t know how to do it)

And debug in R2-R3 wireless if MPLS packets has their EXP-Bit modified, is there any way to log this sniff this?

Is there any way to debug nv2 queues to see packet flow or something?

Best Regards