Index: lib/rubygems/config_file.rb
===================================================================
--- lib/rubygems/config_file.rb	(revision 1413)
+++ lib/rubygems/config_file.rb	(working copy)
@@ -204,6 +204,7 @@
   # Set configuration option +key+ to +value+.
   def []=(key, value)
     @hash[key.to_s] = value
+    instance_variable_set("@#{key.to_sym}", value) if respond_to? key.to_sym
   end
 
   def ==(other) # :nodoc: