No, I don't know how to make Xcode generate one of these jars,
hopefully someone else will.
I would try setting the BUNDLE_AS_JAR build setting in the top-level
target (i.e., the target whose name is the project name) to "YES".
Building the Development configuration should create this bundle jar
in build/Development. I assume that "xcodebuild install…" would
install that bundle jar in /Library/WebObjects/lib, but I've never
paid attention.
