PPPoE over LAG

Hi,

Is there an underlying technical reason why PPPoE is unavailable over a LAG (or over a VLAN over a LAG) interface, or is this limitation just an implementation thing?

Our DSL modems and MBE NTD's only have a single port on them, which isn't enough to connect both HA devices, so I normally run the WAN interfaces inside a VLAN, but this isn't currently possible for PPPoE when the underlying interface is a LAG (PPPoE option missing when configuring a LAG, and grayed out when configuring a VLAN over a LAG)

If this is something that will be corrected in a future version I'll put up with burning a few extra ports on the switch and run PPPoE over additional ports on the Sophos, and reclaim the ports later when the limitation is removed. If it's not going to be fixed any time soon i will forgo LAG and just run everything over a single port. I don't need the bandwidth, LAG is just for a bit of extra redundancy.

Thanks

James