Installing a plugin with different name.

Hi, I'm a plugin developer, and I want users to let install the
plugin using the following syntax.

script/plugin install http://kopal.googlecode.com/hg/

However it installs it in "vendor/plugins/hg/" directory while I want
it to be installed in "vendor/plugins/kopal/" directory. How do I do
that?
I tried passing "--name", but it doesn't work.
- thanks