Index: placement.c
===================================================================
--- placement.c	(revision 22268)
+++ placement.c	(revision 22269)
@@ -54,6 +54,15 @@
 				double rr = tr.rot / PCB_RAD_TO_DEG;
 				pcb_subc_rotate(proto, 0, 0, cos(rr), sin(rr), tr.rot);
 			}
+			if (tr.on_bottom) {
+				int n;
+				pcb_data_mirror(proto->data, 0, PCB_TXM_SIDE, 1);
+				for(n = 0; n < proto->data->LayerN; n++) {
+					pcb_layer_t *ly = proto->data->Layer + n;
+					ly->meta.bound.type = pcb_layer_mirror_type(ly->meta.bound.type);
+					ly->meta.bound.stack_offs = -ly->meta.bound.stack_offs;
+				}
+			}
 
 			htscp_insert(&ctx->subcs, subc, proto);
 		}