When subtracting business time amounts from a date, the result is after the date and not - as one would expect - before this date.
Examples:
Sat Nov 01 00:00:00 CET 2008 + 2 business days -> Tue Nov 04 17:00:00 CET 2008 - OK
Sat Nov 01 00:00:00 CET 2008 - 2 business days -> Sun Nov 02 18:00:00 CET 2008 - unexpected
Sat Nov 01 00:00:00 CET 2008 + 2 business hours -> Mon Nov 03 11:00:00 CET 2008 - OK
Sat Nov 01 00:00:00 CET 2008 -2 business hours -> Mon Nov 03 07:00:00 CET 2008 - unexpected

Data was created by use of small test program:
Date date=new SimpleDateFormat("dd.MM.yyyy").parse("01.11.2008");
String[] durStrs=

{"+ 2 business days", "- 2 business days", "+ 2 business hours", "-2 business hours"}

;
BusinessCalendar calendar= new BusinessCalendar();
for (String durStr: durStrs)

{ Duration duration= new Duration(durStr); Date d= calendar.add(date, duration); System.out.println(" "+date+" "+durStr+" -> "+d); }