thanks for your quick reply.
I think I still must be doing something wrong... In the "Define new multilevel list" dialogue box, I would have to select number 2 under "Click level to modify", right? This is the only way to get the "Include level number from" activated. (It also seems I have to do it in this order, first the "level" selection, then the others. If I try to do it in a different order, it won't display anything under "Include level number".)
I tried to follow your advice step-by-step, first deleting the existing numbering, then selecting the "Include level number", then adding the period after the "1" in the "Enter formatting", and finally the desired number style. Should the last step (selecting the desired style) result in one more number being added to the "formatting" field?
I usually consider myself quite "self-sufficient" with Word and its occasional tricks, but this one is leaving me pretty frustrated and not at all self-confident :D