diff -Nru cln-1.3.1.orig/src/integer/cl_I.h cln-1.3.1.hack/src/integer/cl_I.h
--- cln-1.3.1.orig/src/integer/cl_I.h	2009-05-10 20:32:31 +0000
+++ cln-1.3.1.hack/src/integer/cl_I.h	2010-09-11 13:00:35 +0000
@@ -11,6 +11,16 @@
 #include "base/cl_offsetof.h"
 #include "base/digitseq/cl_DS.h"
 
+#ifdef _MSC_VER
+  // MSVC does not tag "extern cl_private_thing cl_I_constructor_from_UL (uint32 wert);"
+  // in cln/number.h with the cln namespace because it is declared inside the body of
+  // an inlined function (symbol created is >>?cl_I_constructor_from_UL@@YAPAUcl_anything@cln@@K@Z<<)
+  // But cl_I_constructor_from_UL is defined inside cln namespace in cl_I_from_UL.cc
+  // (symbol created is >>?cl_I_constructor_from_UL@cln@@YAPAUcl_anything@1@K@Z<<)
+  // So we get unresolved external symbols on every assignment and constructor operation
+  cln::cl_private_thing cl_I_constructor_from_UL (uint32 wert);
+#endif
+
 namespace cln {
 
 // maximal needed length of a digit sequence for a fixnum
diff -Nru cln-1.3.1.orig/src/integer/conv/cl_I_from_UL.cc cln-1.3.1.hack/src/integer/conv/cl_I_from_UL.cc
--- cln-1.3.1.orig/src/integer/conv/cl_I_from_UL.cc	2009-05-10 20:32:31 +0000
+++ cln-1.3.1.hack/src/integer/conv/cl_I_from_UL.cc	2010-09-11 13:00:24 +0000
@@ -93,4 +93,16 @@
 
 }  // namespace cln
 
+#ifdef _MSC_VER
+  // MSVC does not tag "extern cl_private_thing cl_I_constructor_from_UL (uint32 wert);"
+  // in cln/number.h with the cln namespace because it is declared inside the body of
+  // an inlined function (symbol created is >>?cl_I_constructor_from_UL@@YAPAUcl_anything@cln@@K@Z<<)
+  // But cl_I_constructor_from_UL is defined inside cln namespace in cl_I_from_UL.cc
+  // (symbol created is >>?cl_I_constructor_from_UL@cln@@YAPAUcl_anything@1@K@Z<<)
+  // So we get unresolved external symbols on every assignment and constructor operation
+  cln::cl_private_thing cl_I_constructor_from_UL (uint32 wert) {
+	return cln::cl_I_constructor_from_UL(wert);
+  }
+#endif
+
 #endif