I think that is generally accepted that you do not wear a belt with a waistcoat(vest). Many years ago, however, there was a fashion, here in Scotland, that a minority of kilt wearers used to use. The kilt was worn OVER the bottom of the waistcoat and the belt was put on over the lot. Not a fashion that I liked the look of much and I have not seen it done for many a year. Has any one else seen this?