JRuby on Appengine: jar splitting not working?

I need to upload a jruby web application to appengine, so I use these commands:

cd my/app/path

jruby -S appcfg.rb update .

This throws an error saying:

Found a file too large to upload: "/var/folders/Qv/QvM5YWsvGP84UoFhrVmLyE+++TM/-Tmp-/appcfg5196464172432329417.tmp/vendor/gems/jruby/1.8/cache/jruby-jars-1.6.0.gem". Must be under 10000000 bytes.

Browsing around I found that I need to pass a --enable_jar_splitting flag like this:

jruby -S appcfg.rb 开发者_高级运维 --enable_jar_splitting update .

Still this command fails, with a different error:

INFO: Opening new file: /var/folders/Qv/QvM5YWsvGP84UoFhrVmLyE+++TM/-Tmp-/appcfg7137125152681466424.tmp/WEB-INF/lib/jruby-core-1.6.0-0000.jar
Apr 11, 2011 1:08:12 PM com.google.appengine.tools.util.JarSplitter run
INFO: Closing file after writing 9991985 bytes.
Apr 11, 2011 1:08:12 PM com.google.appengine.tools.util.JarSplitter createOutFile
INFO: Opening new file: /var/folders/Qv/QvM5YWsvGP84UoFhrVmLyE+++TM/-Tmp-/appcfg7137125152681466424.tmp/WEB-INF/lib/jruby-core-1.6.0-0001.jar
Apr 11, 2011 1:08:13 PM com.google.appengine.tools.util.JarSplitter run
INFO: Closing file after writing 9990346 bytes.
Apr 11, 2011 1:08:13 PM com.google.appengine.tools.util.JarSplitter createOutFile
INFO: Opening new file: /var/folders/Qv/QvM5YWsvGP84UoFhrVmLyE+++TM/-Tmp-/appcfg7137125152681466424.tmp/WEB-INF/lib/jruby-core-1.6.0-0002.jar
Apr 11, 2011 1:08:14 PM com.google.appengine.tools.util.JarSplitter run
INFO: Closing file after writing 1316596 bytes.

java.lang.IllegalStateException: Found a file too large to upload: "/var/folders/Qv/QvM5YWsvGP84UoFhrVmLyE+++TM/-Tmp-/appcfg7137125152681466424.tmp/vendor/gems/jruby/1.8/cache/jruby-jars-1.6.0.gem".  Must be under 10000000 bytes.

Seems like it's splitting something... but it's still failing.

Any ideas?