How can I set environment variables in glassfish for a specific application (or domain)

Okay here is my setup:

Running JRUBY (and a JRuby on Rails application) on a glassfish server (not gem!!!). Jruby has been installed via RVM (http://rvm.beginrescueend.com/).

The RoR appl开发者_开发知识库ication has it's own gemset. (managed by rvm)

Now my problem is, that I don't know how to tell glassfish to use a different GEM_HOME and GEM_PATH environment variable.

I can set the JRuby Home (Configuration > Ruby Container), but it's not possible to specify another GEM_HOME or GEM_PATH, as far as i know.

Please help!

GF's environment variables are in:

${glassfish_dir}/glassfish/config/asenv.conf