Okay, that didn't work. Unfortunately, Rails' plugin installer won't install from svn:externals when it's pointed to an HTTP repository (or, rather, the Subversion http repository doesn't tell about its externals). Too bad.

git-svn-id: svn://hamptoncatlin.com/haml/trunk@461 7063305b-7217-0410-af8c-cdc13e5119b9

init.rb

@@ -2,8 +2,6 @@ require 'haml'
 require 'haml/template'
 require 'sass'
 require 'sass/plugin'
-require 'templated_mailer/templated_mailer'
 
 ActionView::Base.register_template_handler('haml', Haml::Template)
-ActionMailer::Base.register_template_extension('haml')
 Sass::Plugin.update_stylesheets

lib/haml/exec.rb

@@ -127,8 +127,16 @@ END
           end
 
           File.open(File.join(dir, 'init.rb'), 'w') do |file|
-            file.puts "require 'rubygems'\n" +
-                      File.read(File.join(File.dirname(__FILE__), '..', '..', 'init.rb'))
+            file.puts <<END
+require 'rubygems'
+require 'haml'
+require 'haml/template'
+require 'sass'
+require 'sass/plugin'
+
+ActionView::Base.register_template_handler('haml', Haml::Template)
+Sass::Plugin.update_stylesheets
+END
           end
 
           puts "Haml plugin added to #{original_dir}"