Index: src_plugins/io_pads/delay_create.c
===================================================================
--- src_plugins/io_pads/delay_create.c	(revision 34599)
+++ src_plugins/io_pads/delay_create.c	(revision 34600)
@@ -656,36 +656,33 @@
 	return nsc;
 }
 
-TODO("this is pads-specific, figure how to handle this; see also: TODO#71");
 static void proto_layer_lookup(pcb_dlcr_t *dlcr, pcb_pstk_shape_t *shp)
 {
-	int level = shp->layer_mask;
-	switch(level) { /* set layer type */
-		case -2: shp->layer_mask = PCB_LYT_TOP | PCB_LYT_COPPER; break;
-		case -1: shp->layer_mask = PCB_LYT_INTERN | PCB_LYT_COPPER; break;
-		case  0: shp->layer_mask = PCB_LYT_BOTTOM | PCB_LYT_COPPER; break;
-		default:
-			{
-				pcb_dlcr_layer_t *ly, **lyp = (pcb_dlcr_layer_t **)vtp0_get(&dlcr->id2layer, level, 0);
-				if ((lyp != NULL) && (*lyp != NULL)) {
-					ly = *lyp;
-					if (!(ly->lyt & PCB_LYT_COPPER)) {
-						shp->layer_mask = ly->lyt;
-						if (ly->lyt & PCB_LYT_MASK)
-							shp->comb = PCB_LYC_SUB;
-					}
-					else {
-						rnd_message(RND_MSG_ERROR, "Padstack prototype can not have a different shape on copper layer %d\n", level);
-					}
-				}
-				else {
-					rnd_message(RND_MSG_ERROR, "Padstack prototype references non-existing layer %d\n", level);
-				}
+	int level = shp->layer_mask, std_lookup = 1;
+
+	if (dlcr->proto_layer_lookup != NULL)
+		std_lookup = dlcr->proto_layer_lookup(dlcr, shp);
+
+	if (std_lookup == 1) {
+		pcb_dlcr_layer_t *ly, **lyp = (pcb_dlcr_layer_t **)vtp0_get(&dlcr->id2layer, level, 0);
+		if ((lyp != NULL) && (*lyp != NULL)) {
+			ly = *lyp;
+			if (!(ly->lyt & PCB_LYT_COPPER)) {
+				shp->layer_mask = ly->lyt;
+				if (ly->lyt & PCB_LYT_MASK)
+					shp->comb = PCB_LYC_SUB;
 			}
-		break;
+			else {
+				rnd_message(RND_MSG_ERROR, "Padstack prototype can not have a different shape on copper layer %d\n", level);
+			}
+		}
+		else {
+			rnd_message(RND_MSG_ERROR, "Padstack prototype references non-existing layer %d\n", level);
+		}
 	}
 }
 
+
 static void pcb_dlcr_create_pstk_protos(pcb_board_t *pcb, pcb_dlcr_t *dlcr, pcb_data_t *dst, const pcb_data_t *src)
 {
 	rnd_cardinal_t n, m;
Index: src_plugins/io_pads/delay_create.h
===================================================================
--- src_plugins/io_pads/delay_create.h	(revision 34599)
+++ src_plugins/io_pads/delay_create.h	(revision 34600)
@@ -91,7 +91,12 @@
 	unsigned subc_relative:1;/* coords are relative to the parent subc */
 } pcb_dlcr_draw_t;
 
-typedef struct {
+typedef struct pcb_dlcr_s pcb_dlcr_t;
+
+struct pcb_dlcr_s {
+	/* caller provided config/callbacks */
+	int (*proto_layer_lookup)(pcb_dlcr_t *dlcr, pcb_pstk_shape_t *shp); /* optional: set shp's layer on special cases and return 0; return 1 for executing the standard layer lookup; required only if there are layer ID special cases, e.g. for -1 */
+
 	/* layers */
 	htsp_t name2layer;
 	vtp0_t id2layer;     /* key=->id, val=(pcb_dlcr_layer_t *) */
@@ -116,7 +121,7 @@
 	/* config */
 	unsigned flip_y:1;              /* if 1, mirror y coordinates over the X axis */
 	unsigned save_netname_objs:1;   /* if 1, save each object:netname pair in ->netname_objs */
-} pcb_dlcr_t;
+};
 
 void pcb_dlcr_init(pcb_dlcr_t *dlcr);
 void pcb_dlcr_uninit(pcb_dlcr_t *dlcr);
Index: src_plugins/io_pads/read.c
===================================================================
--- src_plugins/io_pads/read.c	(revision 34599)
+++ src_plugins/io_pads/read.c	(revision 34600)
@@ -299,6 +299,20 @@
 	return -1;
 }
 
+static int pads_proto_layer_lookup(pcb_dlcr_t *dlcr, pcb_pstk_shape_t *shp)
+{
+	int level = shp->layer_mask;
+	switch(level) { /* set layer type on PADS-specific cases */
+		case -2: shp->layer_mask = PCB_LYT_TOP | PCB_LYT_COPPER; break;
+		case -1: shp->layer_mask = PCB_LYT_INTERN | PCB_LYT_COPPER; break;
+		case  0: shp->layer_mask = PCB_LYT_BOTTOM | PCB_LYT_COPPER; break;
+		default: return 1; /* run the default layer lookup */
+	}
+
+	return 0; /* handled here */
+}
+
+
 static const char *postproc_thermal_lookup(void *uctx, pcb_any_obj_t *obj)
 {
 	htpp_t *ht = uctx;
@@ -359,6 +373,7 @@
 	pcb_dlcr_init(&rctx.dlcr);
 	rctx.dlcr.flip_y = 1;
 	rctx.dlcr.save_netname_objs = 1;
+	rctx.dlcr.proto_layer_lookup = pads_proto_layer_lookup;
 
 	/* read the header */
 	if (pads_parse_header(&rctx) != 0) {