Cannot call bundle by jruby-complete-1.7.21.jar

Question

I've read http://spin.atomicobject.com/2013/04/24/bundler-jruby-complete/ and installed faraday, rspec and bundler gems with commands like:

export GEM_HOME=/var/lib/tomcat6/shared/gems
export GEM_PATH=/var/lib/tomcat6/shared/gems
java -jar jruby-complete-1.7.21.jar -S gem install bundler

And I see these gems in the list provided by

java -jar jruby-complete-1.7.21.jar -S gem list

I also can require files from these gems in inline jruby script, called through JSR223 from Activiti BPM, which is written in java.

But I failed to run gem binaries, e.g. bundle such way:

export BUNDLE_GEMFILE=/var/lib/tomcat6/shared/gems
java -jar jruby-complete-1.7.21.jar -S bundle

How can I use bundler to manage jruby-complete gems?