Tvheadend

Hello Im struggling with getting the episode-num passed through to the exported http://TVH IP/xmltv/channels list.

Ive tried the tv_grab_na_dd and tv-grab_zz_sdjson grabbers into the socket and internal and the exported one doesn't contain the tag, below is the schedules direct XML example:

<programme start="20200108003700 -0500" stop="20200108010600 -0500" channel="I60123.labs.zap2it.com">
<title lang="en">Nightline</title>
<desc lang="en">In-depth reporting on news and events with Juju Chang and Byron Pitts.</desc>
<category lang="en">Talk</category>
<category lang="en">News</category>
<category lang="en">Interview</category>
<category lang="en">Series</category>
*<episode-num system="dd_progid">SH00003138.0000</episode-num>*
<previously-shown />
<subtitles type="teletext" />
</programme>

Exported output;

<programme start="20200110003700 -0500" stop="20200110010600 -0500" channel="d14ad93458c8890e7f39628ad52ac937">
<title lang="eng">Nightline</title>
<desc lang="eng">
In-depth reporting on news and events with Juju Chang and Byron Pitts.
</desc>
</programme>


Is this customizable can fields be exported as they are found for channels or does someone have a way to massage this?

Thanks