[dev] Configuration of TIME and DATE formats?

I have not been able to find a way to modify the way a DATE and a TIME is displayed, is it possible to change the formatting of these in OTRS 1.3.1? What I want is "YYYY-MM-DD" for dates, and "HH:MM" (24h) for time. Alternatively, I'd like "WWW, MMM DD YYYY" for dates ("Fri, Oct 01 2004"). -joho