I have the same problem. Plugins used to work when running Serviio on a Windows 7 pc., but none of the plugins seem to work when running on my Synology DS412+. Not any online webresource or livestream does show up in mthe library of the DLNA client. For instance, i have TVHeadend running, i can open the stream
http://10.0.0.180:9981/stream/channelis/140 in VLC, but putting it in Serviio's online resources never works for me.
Serviio 1.4 on Synologu DS412+