hi,
it seems a bit odd that Huawei switches add a vlan id of 350 to untagged packets, as this would mean the packets are not untagged any longer and thus all devices on the way would try to switch them into vlan 350.
with cisco you can set a native vlan and all packets sourced from this vlan are sent untagged.
if Huawei really adds all untagged packets to vlan 350, i guess you would need to add a vlan 350 to the cisco devices!?
maybe there is someone who has more experience with Huawei than me!