Creating/copying files via WebDAV with OS X generates 0-byte files

I'm getting 0-byte files with a variety of error messages from OS X when I try to copy files via WebDAV.

Steps to reproduce:
1) in modeshape-web-jcr-webdav-war, mvn cargo:run
2) In OS X Finder, connect to server (command-k) with http://localhost:8090/webdav-jcr/webdav_repo/default and username/pass dnauser/password
3) mkdir /Volumes/default/foo
4) cp /path/to/any/file.txt /Volumes/default/foo/

Step 4 fails with a "Resource busy" error in the terminal. In Finder, usually something like "The operation can't be completed because the item 'file.txt' is in use." Step 4 does generate a 0-byte file in the correct location with the correct filename however.

I'm not seeing a stacktrace from MODE. On OS X, in /var/log/system.log, I'm seeing messages like:

webdavfs_agent[17234]: unexpected statusCode 423
kernel[0]: cp[17453] Unable to quarantine `file.txt': 1

I initially thought this was something to do w/ improper handling of OS X/Finder file metadata, because occasionally the error I see is "cp: /path/to/any/file.txt: could not copy extended attributes to ./file.txt: Operation not permitted". However, using ditto, e.g.:

ditto --norsrc --noextattr --noacl /path/to/any/file.txt /Volumes/default/foo/

still fails, creating 0-byte files.

I gather from the screenshots at https://docs.jboss.org/author/display/MODE/Using+Repositories+with+WebDAV+in+AS7 that MODE's webdav support used to work with OS X.