hotmail has a bad sniffer than can't tell that kmeleon is a gecko browser
to fix the problem permanently, download autoagent switcher that will make hotmail behave
http://kmext.sf.net
auto agent switcher is filed under enhancements
extract the 7z extension in kmeleon's folder and restart kmeleon
to make sure the extension was installed properly, go to tools>user agent>auto switcher must be checked
now browse hotmail normally and compose should work