diff --git a/UI/Common/GNUmakefile.preamble b/UI/Common/GNUmakefile.preamble
index a4d2bb3a9..eaf1c03cc 100644
--- a/UI/Common/GNUmakefile.preamble
+++ b/UI/Common/GNUmakefile.preamble
@@ -18,4 +18,4 @@ CommonUI_BUNDLE_LIBS += \
 	-lNGObjWeb	\
 	-lNGMime	\
 	-lNGStreams -lNGExtensions -lEOControl	\
-	-lXmlRpc -lDOM -lSaxObjC
+	-lXmlRpc -lDOM -lSaxObjC -lWOExtensions
diff --git a/UI/SOGoUI/GNUmakefile.preamble b/UI/SOGoUI/GNUmakefile.preamble
index 04320edd6..d54766e7c 100644
--- a/UI/SOGoUI/GNUmakefile.preamble
+++ b/UI/SOGoUI/GNUmakefile.preamble
@@ -10,7 +10,7 @@ libSOGoUI_LIBRARIES_DEPEND_UPON += \
 	-lNGObjWeb	\
 	-lNGMime	\
 	-lNGStreams -lNGExtensions -lEOControl \
-	-lXmlRpc -lDOM -lSaxObjC
+	-lXmlRpc -lDOM -lSaxObjC -lWOExtensions
 
 SYSTEM_LIB_DIR += -L/usr/local/lib -L/usr/lib
 ADDITIONAL_INCLUDE_DIRS += -I../../SoObjects