After I heard from you that Schovenberg might possibly a place name in the Netherlands or Germany, I went to look at www.multimap.com
, and I couldn't find any place called Schovenberg. BUT, I did find a place called Schaufenberg, and that was close to the town of Hückelhoven (which you mentioned earlier). Maybe the original spelling of Schovenberg is Schaufenberg, and then maybe the surname was made more Dutch (because Schovenberg sounds more Dutch than German) by its bearers or people in the environment.
What do you think?
P.S.: I myself live close to Sittard (in the Netherlands), so both the places Hückelhoven and Schaufenberg aren't all that far away from me (and for so far I know, most of my family comes from Waldfeucht in Germany).