Since firmware version 18.104.22.168, Vigor130 supports bridging VLAN tag from WAN to LAN while doing PPPoE Passthrough or MPoA Bridge. It allows VLAN Tag configuration on the LAN device instead.
To bridge the VLAN tag, go to Internet Access >> General Setup, enable Customer Tag for the DSL mode you use, but DO NOT enter the tag value.
Now, the VLAN tag on WAN traffic will be kept for the LAN device while doing PPPoE Pass-through or MPoA Bridge. And the LAN device should have the VLAN configuration which ISP request.