avoiding use + % in filename

From Gregor McNish http://moodle.org/user/view.php?id=479174&course=5

've just started looking at the app. A small issue with uploading – the file uploada fine, but the filename is set to something like "2011-09-12%20012112%20%2B0000.jpg", and the + character seems to cause issues when actually using the file within moodle.

If I change the filename to remove the + when embedding the image it works fine.

We're using IIS on windows server to serve moodle.

There's a useful blog post here http://blogs.iis.net/robert_mcmurray/archive/2011/04/27/bad-characters-to-use-in-web-based-filenames.aspx

which references RFC1296 which includes + (among others) as a reserved character in URLs.