How can I insert a radio stream in Euro Truck Simulator 2?

I've barely discovered the radio streaming function on Euro Truck Simulator 2 and want to put this in the stream along with this, but have had no success. I've done the "stream_data[xx]: "linkforstreamhere|name|genre|language|" format, but it won't work. Is there something I'm doing wrong or can I not use these links?

You can't use those links. Euro Truck Simulator 2 requires links to the actual MP3 audio steams, and links in your post are to ordinary web pages that host a custom Flash player. In order to listen to a streaming radio station through the game you're going to need to track down the actual raw URL for the station, assuming one exists. It needs to serve the audio in MP3 format, not AAC, FLV, Windows Media, or any kind of playlist (.PLS or .M3U). I was able to track down a URL for your first station, 104.9 JACK fm, on a site called CRadios. The other link doesn't seem to for an actual over-the-air radio station, it's the site of a company that licences the "JACK fm" name to radio stations and seems to provide most, if not all, of their content.

Here's an example live_streams.sii that includes the URL I found for 104.9 JACK fm:

SiiNunit
{
#
# Stream data format: "URL of the live stream | Name for the radio as listed in Radio screen | Genre | Language | Bitrate"
#
# !!! WARNING !!!  mms streams are not supported!
#
# remove the leading '#' character on the "stream_data[]" line below and enter
# a correct URL of the stream to have the Internet radio offered in the Radio screen
# you can enter multiple lines in the same format, each defining additional radios
#

live_stream_def : .live_streams {
# stream_data[]: "URL of mp3 live stream|Radio name|Genre|Language|Bitrate"
stream_data[]: "http://4893.live.streamtheworld.com:3690/SPARKNET_SC|104.9 JACK FM|Adult Hits|English|96k"
stream_data[]: "http://streamerepsilon.jazz.fm:8000|Jazz FM91|Jazz|English|96k"
stream_data[]: "http://streamergamma.jazz.fm:8008/|Jazz FM91 Oscar Petterson|Jazz|English|64k"
stream_data[]: "http://itori.animenfo.com:443/|Anime NFO|Anime|English|192k"

}
}

Note that the 104.9 JACK FM URL stopped working for me after a while, so this particular stream may not work reliably. I've provided a few more streaming stations in case the first one doesn't work and to show how to add multiple radio stations.

This file should be put in the Euro Truck Simulator 2 folder of your Documents folder. Eg: C:\Users\Ross Ridge\Documents\Euro Truck Simulator 2\live_streams.sii"