applying TwitterBootstrap and LESS

Rails 3.1.3

I'm trying to apply TwitterBootstrap and LESS

bundle install the following
  gem 'less-rails-bootstrap', '~> 2.0.4'

Normal Twitter bootstrap is applied without problem.
But I need to change themes to my own creation or downloaded from

http://bootswatch.com/

My question is WHERE exactly should I place the LESS setting as a
separate file?

Of course, in assets/stylesheet directory, but I placed it there, and
checked the source code of the generated web page. For some reason, the
normal twitter bootstrap setting comes AFTER the LESS I created.

The order of reading files seems important. Could anyone give me tips
for this?

soichi