Your right, but there is probably a way to use /etc/modprobe.d to get the same thing done. It may even be unnecessary.
I'd probably skip the stip and continue with the others until I found out if it was going to work or fail.
If fail I would come back and tinker.
Perhaps I'd google "slackware modprobe.conf" then I'd tinker with that research.
And having the hardware, I'd know if my tinkering was working or not as I went.
That's probably why the responses you get are so unsatifactory to you. You are not a tinkerer, but looking for specific instruction.
However, since none of us have the hardware, we can not offer specific instruction.
There are a couple no tinker options.
1. Use mythbuntu. This is a distribution with tv cards in mind. It probably has the best compatibility to the most tvcards of any distro.
2. Take up uelsk8s on his offer, from the other thread. Send him your tv card, let him tinker, and he will build what you need into a package that can be downloaded and installed through gslapt, or something just as convenient and send your card back to you.
3. I think, back and forth forum posts is a bad way to tinker. If you want to continue, tinkering but with help, then starting on Monday of next week I am on vacation, and if you are willing we could connect using "Teamviewer" and if allowed remote access to your machine I can tinker for you.
Full disclosure....Uelsk8's (option 2) is smarter than me.

But this way you won't have to send your card anywhere.
However, you will need a highspeed internet connection.