This problem was fixed in the AbstractHttpRetrievalMacro (for v1 macros) in 2.0 (CONF-4006), but not in BaseHttpRetrievalMacro (for v2 macros). It should be simple to port this across.

For information on this property, see: http://java.sun.com/j2se/1.4.2/docs/guide/net/properties.html