diff --git a/sys/thing/properties.h b/sys/thing/properties.h
index c472af5..be7a6cd 100644
--- a/sys/thing/properties.h
+++ b/sys/thing/properties.h
@@ -13,6 +13,12 @@
 #define F_SET_METHOD    2
 #define F_QUERY_METHOD  3
 
+// The following are used as type flags for Set(), but they do not index
+// <prop>, therfore they have a negative sign.
+//
+// F_SET_MAPPER sets F_SET_METHOD, but additionally sets the mode SETMAPPED
+// automatically
+#define F_SET_MAPPER    -F_SET_METHOD
 // Flags for Set() to modify/manipulate F_MODE of a property in bit-wise
 // manner
 #define F_MODE_AS       4
@@ -23,6 +29,7 @@
 #define PROTECTED       128  // only this_object() can change the values
 #define SECURED         256  // like PROTECTED, but never resetable
 #define NOSETMETHOD     512  // Keine Set-Methode => Nicht mofifizierbar
+#define SETMAPPED       0x4000 // Setmethod only maps, not sets
 // Problem with the following: shadows, default methods etc. may change the
 // result at runtime and they do not save that much time (or even at all?)
 // because of the apply cache of the driver. Not used since 1995. But