I try to instal the IPTV and an IGMPproxy on my SME.
In that case, your post is off-topic for this forum.
The IGMPproxy already runs, however, me do not know like me pppoe informs vlan eth1.8 to use. Where do I find parametre for the interface pppoe? where can I brag who should be used ethx for ppp0?
I don't know what you are asking here. It might be easier for you if you use the forum in your native language, which I suspect might be German.
I can tell you, however, that SME server has no support for VLANs, including for operating pppoe over VLAN.