diff --git a/tools/vio2sf/readme.txt b/tools/vio2sf/readme.txt
new file mode 100644
index 000000000..693c61b7b
--- /dev/null
+++ b/tools/vio2sf/readme.txt
@@ -0,0 +1,4 @@
+First build every project in vio2sf.dsw. This will include the vio2sf project which will copy vio2sf.bin into all the plugin dirs.
+Then build foo_input_vio2sf from vio2sf.sln. This plugin my be built in a newer msvc. 
+It has a dependency on vio2sf, which will then overwrite all vio2sf.bin in all directories with a vc9 version.
+This is safe since it doesn't import any CRT DLL, and it probably runs a little faster.