diff --git a/bin/Packager/Nsis/NullsoftInstaller.nsi b/bin/Packager/Nsis/NullsoftInstaller.nsi
--- a/bin/Packager/Nsis/NullsoftInstaller.nsi
+++ b/bin/Packager/Nsis/NullsoftInstaller.nsi
@@ -197,3 +197,5 @@
 
 SectionEnd
 
+;  allow to define additional Un.sections
+@{un_sections}
\ No newline at end of file
diff --git a/bin/Packager/NullsoftInstallerPackager.py b/bin/Packager/NullsoftInstallerPackager.py
--- a/bin/Packager/NullsoftInstallerPackager.py
+++ b/bin/Packager/NullsoftInstallerPackager.py
@@ -73,6 +73,7 @@
         defines.setdefault("srcdir", self.archiveDir())# deprecated
         defines.setdefault("registy_hook", "")
         defines.setdefault("sections", "")
+        defines.setdefault("un_sections", "")
         defines.setdefault("sections_page", "")
         defines.setdefault("preInstallHook", "")