Using LEO on a daily base, I tried to find a way to optimize looking up a translation through Firefox. I already knew that I can use a URL like 'g java' to do a Google search on 'Java', and I wanted to achieve the same functionality for LEO using 'l haus' since these keyword searches are super convenient.
Surprisingly, it only took two minutes to google the web and find and apply a solution:
http://kb.mozillazine.org/Using_keyword_searches
Bookmark Name: LEO
Location: http://dict.leo.org/?search=%s
Keyword: l
This makes Ctrl-T Ctrl-L my favorite keyboard shortcut.