But the point is all the over methods previously on different distos have worked fine, why is it so weird in SLES.
...because SuSE start up is different. A bit of history, when SuSE started up, they were a Slackware distributor; when they decided that they wanted to do their own distro, they quite liked the start up arrangement of the BSDs, so their arrangement is a hybrid of the two.
Of course, this attempt to cherry pick the best of two different systems to have their cake and eat it; what this ignores is that it confuses people.
If you start stuff up via yast, that works; if you don't, read the documentation, otherwise you will find you are fighting against yast, which doesn't always like people doing things behind its back.