Is it possible to add pppoe to a bridge?

[Peter]

Even if a bridge is empty it seems impossible to add pppoe to it. This 
doesn't change if the first bridge member has an MTU identical to that 
of the pppoe interface (thank you to Martin  Reindl for a patch 
enabling  mtu changes on  Sun quad  ethernet). For my own, and anyone 
else's reference, the bridge's own MTU is hardcoded to ETHERMTU (1500).

Now, I can go through the source to if_bridge.c and find the definitive 
answer, but I thought I'd ask here in case anyone had an immediate 
answer, even if delving into the depths of OpenBSD is new knowledge for 
me. The bridge and brconfig man pages aren't illuminating in this regard.

Alternatively, it would be good to know if I'm doing something foolish, 
if I find a way to get the source to accept pppoe interfaces - could 
there be a hidden side effect?

PK