Tvheadend

Hi all
I'm a bit lost with the logic behind the management of iptv channels in tvheaded.
First the goal: I would like to transcode a DVB-T channel by gstreamer into a pipe that I want to stream as an IPTV channel in tvheadend itself.
So what I did is to create an IPTV network and then create a mux on this IPTV network. In this mux I set the pipe:// launch script (which I have verified that works without the pipe://). But now I'm lost. How can mape a service (= a channel) over this mux? To summarize: how can I play this transcoded pipe from a front end connected to tvhedend?
If I force scan the network, this is what I get from the logs:

2017-02-27 14:10:55.174 [   INFO]:spawn: Executing "/usr/bin/gst-launch-1.0" 
2017-02-27 14:10:55.980 [   INFO]:mpegts: 698MHz in DVB-T Network - tuning on Sky IT Digital Key (green led) : DVB-T #0
2017-02-27 14:10:55.984 [   INFO]:subscription: 01E7: "epggrab" unsubscribing
2017-02-27 14:10:55.986 [   INFO]:subscription: 01ED: "HTTP" subscribing on channel "Canale5", weight: 100, adapter: "Sky IT Digital Key (green led) : DVB-T #0", network: "DVB-T Network", mux: "698MHz", service: "Canale5", profile="mpeg2", hostname="192.168.182.212", username="menion", client="GStreamer souphttpsrc libsoup/2.48.0" 
2017-02-27 14:10:56.265 [   INFO]:transcode: 0007: 1:MPEG2VIDEO ==> Passthrough
2017-02-27 14:10:56.265 [   INFO]:transcode: 0007: 2:MPEG2AUDIO ==> Passthrough
2017-02-27 14:10:56.265 [   INFO]:transcode: 0007: 3:MPEG2AUDIO ==> Passthrough
2017-02-27 14:10:56.374 [   INFO]:transcode: 0007: 1:MPEG2VIDEO ==> Passthrough
2017-02-27 14:10:56.374 [   INFO]:transcode: 0007: 2:MPEG2AUDIO ==> Passthrough
2017-02-27 14:10:56.374 [   INFO]:transcode: 0007: 3:MPEG2AUDIO ==> Passthrough
2017-02-27 14:10:56.787 [ NOTICE]:mpegts: mux 698MHz in DVB-T Network old params DVB-T freq 698000000 bw 8MHz cons QAM/64 hier NONE code_rate 2/3:NONE guard 1/32 trans 8k plp_id -1 (00002010)
2017-02-27 14:10:56.787 [ NOTICE]:mpegts: mux 698MHz in DVB-T Network new params DVB-T freq 698000000 bw 8MHz cons QAM/64 hier NONE code_rate 3/4:NONE guard 1/4 trans 8k plp_id -1 (00002010)
2017-02-27 14:10:57.081 [WARNING]:libav: Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
2017-02-27 14:10:57.081 [WARNING]:libav: Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
2017-02-27 14:10:57.081 [WARNING]:libav: Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
2017-02-27 14:10:57.105 [WARNING]:tsfix: The timediff for TELETEXT is big (3215596872), using current dts
2017-02-27 14:11:10.161 [   INFO]:mpegts: Canale 5 - pipe in Local pipe - scan no data, failed
2017-02-27 14:11:10.161 [   INFO]:subscription: 01EC: "scan" unsubscribing
2017-02-27 14:11:10.184 [WARNING]:webui: Stop streaming /stream/channelnumber/5?profile=mpeg2, muxer reported errors
2017-02-27 14:11:10.187 [   INFO]:subscription: 01ED: "HTTP" unsubscribing from "Canale5", hostname="192.168.182.212", username="menion", client="GStreamer souphttpsrc libsoup/2.48.0" 
2017-02-27 14:11:11.162 [   INFO]:mpegts: 698MHz in DVB-T Network - tuning on Sky IT Digital Key (green led) : DVB-T #0
2017-02-27 14:11:11.162 [   INFO]:subscription: 01EF: "epggrab" subscribing to mux "698MHz", weight: 4, adapter: "Sky IT Digital Key (green led) : DVB-T #0", network: "DVB-T Network", service: "Raw PID Subscription" 
2017-02-27 14:11:12.784 [ NOTICE]:mpegts: mux 698MHz in DVB-T Network old params DVB-T freq 698000000 bw 8MHz cons QAM/64 hier NONE code_rate 2/3:NONE guard 1/32 trans 8k plp_id -1 (00002010)
2017-02-27 14:11:12.784 [ NOTICE]:mpegts: mux 698MHz in DVB-T Network new params DVB-T freq 698000000 bw 8MHz cons QAM/64 hier NONE code_rate 3/4:NONE guard 1/4 trans 8k plp_id -1 (00002010)

Is it possible that the transcoded ts file is missing of some information?
Bye