So in webgrab folder you edit WebGrab++.config.xml to add your own channels right?
In that file the name of the channel you are grabbing should match the name of the channel in the m3u list.
I'll leave an example of my WebGrab++.config.xml for spanish channels
<settings>
<timespan>2</timespan> <---- 2 means it grabs for 3 days 3=4 days and so on
<update></update>
<filename>whateverpathyouwant\xmltv.xml</filename>
<channel update="i" site="elmundo.es" site_id="2" xmltv_id="SP: ANTENA 3">SP: ANTENA 3</channel>
<channel update="i" site="guia-tv.es" site_id="bein-sports" xmltv_id="bein Sports">bein Sports</channel>
<channel update="i" site="elmundo.es" site_id="155" xmltv_id="SP: BARCA TV">SP: BARCA TV</channel>
<channel update="i" site="elmundo.es" site_id="665" xmltv_id="SP: BOING">SP: BOING</channel>
<channel update="i" site="elmundo.es" site_id="64" xmltv_id="SP: CALLE 13">SP: CALLE 13</channel>
<channel update="i" site="elmundo.es" site_id="61" xmltv_id="SP: CANAL HOLLYWOOD">SP: CANAL HOLLYWOOD</channel>
<channel update="i" site="elmundo.es" site_id="135" xmltv_id="SP: CANAL ODISEA">SP: CANAL ODISEA</channel>
<channel update="i" site="elmundo.es" site_id="505" xmltv_id="SP: CLAN TV">SP: CLAN TV</channel>
<channel update="i" site="elmundo.es" site_id="493" xmltv_id="SP: COMEDIA CENTRAL">SP: COMEDIA CENTRAL</channel>
<channel update="i" site="elmundo.es" site_id="496" xmltv_id="SP: CUATRO">SP: CUATRO</channel>
<channel update="i" site="elmundo.es" site_id="175" xmltv_id="SP: DISNEY CHANNEL">SP: DISNEY CHANNEL</channel>
<channel update="i" site="elmundo.es" site_id="292" xmltv_id="SP: DISNEY JUNIOR">SP: DISNEY JUNIOR</channel>
<channel update="i" site="elmundo.es" site_id="174" xmltv_id="SP: DISNEY XD">SP: DISNEY XD</channel>
<channel update="i" site="elmundo.es" site_id="697" xmltv_id="SP: DIVINITY">SP: DIVINITY</channel>
<channel update="i" site="elmundo.es" site_id="709" xmltv_id="SP: ENERGY">SP: ENERGY</channel>
<channel update="i" site="elmundo.es" site_id="202" xmltv_id="SP: FOX">SP: FOX</channel>
<channel update="i" site="elmundo.es" site_id="660" xmltv_id="SP: FOX LIFE">SP: FOX LIFE</channel>
<channel update="i" site="elmundo.es" site_id="148" xmltv_id="SP: HISTORIA">SP: HISTORIA</channel>
<channel update="i" site="elmundo.es" site_id="3" xmltv_id="SP: LA 1">SP: LA 1</channel>
<channel update="i" site="elmundo.es" site_id="4" xmltv_id="SP: LA 2">SP: LA 2</channel>
</settings>
If you can see i changed the last 2 values in every line with my own m3u names. Otherwise is not going to work.
In your example
#EXTM3U
#EXTINF:-1 tvg-ID="3" tvg-name="SP: LA 1" tvg-logo="http://logoss.ddns.net/html/spnew/tve1_madrid.png" group-title="Spain",SP: LA 1
http://xxxxxxxxxxxxxxxxxxx.ts
changing tvg-ID doesn't work. As i said before name of the channel in the m3u list (in this example SP: LA 1) needs to match the name of the channel that is being grabbed in WebGrab++.config.xml