I've found that with my bash clone job script [1] that when I POST a config.xml file that I've first downloaded from hudson using curl, that any ant build properties (or targets) that are separated with a newline have the newline removed during the upload/import process. For targets, this isn't as big of a deal because they can be separated by a space, but for ant properties (the -D arguments), this is a big deal because they need to be separated by a newline. I've confirmed that the downloaded file has the newline, so it seems the newline is being lost when the upload/import happens.

[1] http://wiki.jenkins-ci.org/display/JENKINS/Bash+Job+Clone+script