I don't remember the part number, but Volvo sells those buttons seperately, or at least they did when I worked in a Volvo dealership in 98 and 99. I have installed a few that i sourced from Volvo on Fords.
i went to auto zone and looked in their plastic HELPS part shelf and could not find the correct one.. but this is what i did... got one that was similar and being as its plastic i put it on the belt and then used the soldering iron to cut the point off of the end when it was sticking out too far.... amazing what you can do with a soldering iron from harbor freight for $4.99.... almost like making your own parts now tha they all come in plastic... years ago people would have laughed if it was mentioned that parts were plastic..... i did this about 2 yrs. ago and the seat belt button is still there....
