diff --git a/debian/libmono-security4.0-cil.dirs b/debian/libmono-security4.0-cil.dirs
new file mode 100644
index 0000000000..6783cf3a17
--- /dev/null
+++ b/debian/libmono-security4.0-cil.dirs
@@ -0,0 +1 @@
+/etc/mono/certstore
diff --git a/debian/libmono-security4.0-cil.links b/debian/libmono-security4.0-cil.links
new file mode 100644
index 0000000000..c90182efff
--- /dev/null
+++ b/debian/libmono-security4.0-cil.links
@@ -0,0 +1 @@
+/etc/mono/certstore	/usr/share/.mono
diff --git a/debian/libmono-security4.0-cil.preinst b/debian/libmono-security4.0-cil.preinst
new file mode 100644
index 0000000000..845136caf4
--- /dev/null
+++ b/debian/libmono-security4.0-cil.preinst
@@ -0,0 +1,18 @@
+#!/bin/sh -e
+
+# Move old CA cert store to new location in /etc, if it exists in /usr
+
+OLD_CERTDIR=/usr/share/.mono
+NEW_CERTDIR=/etc/mono/certstore
+
+if [ "$1" = "upgrade" -o "$1" = "install" ] ; then
+   if [ -d "$OLD_CERTDIR" ] ; then
+     echo "Found cert store in old location, moving to $NEW_CERTDIR"
+     mkdir -p $NEW_CERTDIR/
+     mv $OLD_CERTDIR/* $NEW_CERTDIR/
+     rm -fr $OLD_CERTDIR/
+   fi
+fi
+
+#DEBHELPER#
+