The V1R2 version does not support this configuration and the V1R3 version starts to support it.
1.12.1 Configuration Information:
On PE1:
#
Vsi test static
 Pwsignal ldp
  Vsi-id 1
  Peer 111.111.111.111
 Encapsulation ethernet
#
Interface GigabitEthernet2/0/16.1
 Qinq mapping vid 16 map-vlan vid 18 (change the V1R6, V2R1 command line to qinq mapping vid 16 map-vlan vid 18)
 L2 binding vsi test
#
On PE2:
#
Vsi test static
 Pwsignal ldp
  Vsi-id 1
  Peer 90.90.90.90
 Encapsulation ethernet
#
Interface GigabitEthernet4/0/16.1
 Qinq mapping vid 19 map-vlan vid 20 (change the V1R6, V2R1 command line to qinq mapping vid 19 map-vlan vid 20)
 L2 binding vsi test
#
1.12.2 Packets Entering the Tunnel:
The packet encapsulated by CE1 is VLAN 16:
 
After receiving the packet, PE1 strips the VLAN in the original packet and then encapsulates the MPLS label and other information and forwards it to PE2:
 
If the packets sent by CE1 are double-layered VLANs, only the outer VLANs are processed, and the inner VLANs are always unchanged. If the packets sent by CE1 are not VLANs, they are discarded.
1.12.3 Packets from the Tunnel:
After PE2 receives the packet from PE1, PE2 strips off the MPLS-related encapsulation information and then encapsulates the vlan, which is the map, that is configured on the local device, namely 19, into the packet and forwards it to CE2:
 
1.12.4 Supplementary explanation:
V1R2 does not support Ethernet VSIs bound to a single-tagged VLAN mapping sub-interface. V1R3 starts to support V1R3. The preceding implementation method is for V1R3. If packets sent by CE1 are VLAN-less, they are discarded.

The summary of  Handling of VLANs in Packets in Various Versions of L2VPN Configurations .http://forum.huawei.com/enterprise/en/forum.php?mod=viewthread&tid=453137