Index: pstk_compat.c
===================================================================
--- pstk_compat.c	(revision 20900)
+++ pstk_compat.c	(revision 20901)
@@ -137,7 +137,7 @@
 		free(shp->data.poly.x);
 }
 
-pcb_pstk_t *pcb_pstk_new_compat_via(pcb_data_t *data, pcb_coord_t x, pcb_coord_t y, pcb_coord_t drill_dia, pcb_coord_t pad_dia, pcb_coord_t clearance, pcb_coord_t mask, pcb_pstk_compshape_t cshape, pcb_bool plated)
+pcb_pstk_t *pcb_pstk_new_compat_via(pcb_data_t *data, long int id, pcb_coord_t x, pcb_coord_t y, pcb_coord_t drill_dia, pcb_coord_t pad_dia, pcb_coord_t clearance, pcb_coord_t mask, pcb_pstk_compshape_t cshape, pcb_bool plated)
 {
 	pcb_pstk_proto_t proto;
 	pcb_pstk_shape_t shape[5]; /* max number of shapes: 3 coppers, 2 masks */
@@ -731,7 +731,7 @@
 }
 
 
-pcb_pstk_t *pcb_old_via_new(pcb_data_t *data, pcb_coord_t X, pcb_coord_t Y, pcb_coord_t Thickness, pcb_coord_t Clearance, pcb_coord_t Mask, pcb_coord_t DrillingHole, const char *Name, pcb_flag_t Flags)
+pcb_pstk_t *pcb_old_via_new(pcb_data_t *data, long int id, pcb_coord_t X, pcb_coord_t Y, pcb_coord_t Thickness, pcb_coord_t Clearance, pcb_coord_t Mask, pcb_coord_t DrillingHole, const char *Name, pcb_flag_t Flags)
 {
 	pcb_pstk_t *p;
 	pcb_pstk_compshape_t shp;
@@ -747,7 +747,7 @@
 	else
 		shp = PCB_PSTK_COMPAT_ROUND;
 
-	p = pcb_pstk_new_compat_via(data, X, Y, DrillingHole, Thickness, Clearance/2, Mask, shp, !(Flags.f & PCB_FLAG_HOLE));
+	p = pcb_pstk_new_compat_via(data, id, X, Y, DrillingHole, Thickness, Clearance/2, Mask, shp, !(Flags.f & PCB_FLAG_HOLE));
 	p->Flags.f |= Flags.f & PCB_PSTK_VIA_COMPAT_FLAGS;
 	for(n = 0; n < sizeof(Flags.t) / sizeof(Flags.t[0]); n++) {
 		int nt = PCB_THERMAL_ON, t = ((Flags.t[n/2] >> (4 * (n % 2))) & 0xf);
Index: pstk_compat.h
===================================================================
--- pstk_compat.h	(revision 20900)
+++ pstk_compat.h	(revision 20901)
@@ -12,8 +12,9 @@
 	PCB_PSTK_COMPAT_INVALID
 } pcb_pstk_compshape_t;
 
-/* Create a padstack that emulates an old-style via - register proto as needed */
-pcb_pstk_t *pcb_pstk_new_compat_via(pcb_data_t *data, pcb_coord_t x, pcb_coord_t y, pcb_coord_t drill_dia, pcb_coord_t pad_dia, pcb_coord_t clearance, pcb_coord_t mask, pcb_pstk_compshape_t shp, pcb_bool plated);
+/* Create a padstack that emulates an old-style via - register proto as needed
+   if id <= 0, allocate a new id automatically */
+pcb_pstk_t *pcb_pstk_new_compat_via(pcb_data_t *data, long int id, pcb_coord_t x, pcb_coord_t y, pcb_coord_t drill_dia, pcb_coord_t pad_dia, pcb_coord_t clearance, pcb_coord_t mask, pcb_pstk_compshape_t shp, pcb_bool plated);
 
 /* Convert an existing padstack to old-style via and return broken down parameters */
 pcb_bool pcb_pstk_export_compat_via(pcb_pstk_t *ps, pcb_coord_t *x, pcb_coord_t *y, pcb_coord_t *drill_dia, pcb_coord_t *pad_dia, pcb_coord_t *clearance, pcb_coord_t *mask, pcb_pstk_compshape_t *cshape, pcb_bool *plated);
@@ -30,8 +31,9 @@
 
 #define PCB_PSTK_VIA_COMPAT_FLAGS (PCB_FLAG_CLEARLINE | PCB_FLAG_SELECTED | PCB_FLAG_FOUND | PCB_FLAG_WARN | PCB_FLAG_USETHERMAL | PCB_FLAG_LOCK)
 
-/* Create a padstack that mimics the old gEDA/PCB via (or pin). Should not
-   be used anywhere but io_pcb and io_lihata. */
-pcb_pstk_t *pcb_old_via_new(pcb_data_t *data, pcb_coord_t X, pcb_coord_t Y, pcb_coord_t Thickness, pcb_coord_t Clearance, pcb_coord_t Mask, pcb_coord_t DrillingHole, const char *Name, pcb_flag_t Flags);
+/* Create a padstack that mimics the old gEDA/PCB via (or pin).
+   If id <= 0, allocate a new ID automatically.
+   Should not be used anywhere but io_pcb and io_lihata. */
+pcb_pstk_t *pcb_old_via_new(pcb_data_t *data, long int id, pcb_coord_t X, pcb_coord_t Y, pcb_coord_t Thickness, pcb_coord_t Clearance, pcb_coord_t Mask, pcb_coord_t DrillingHole, const char *Name, pcb_flag_t Flags);
 
 #endif