thinking_sphinx don't look for models in vendor/plugins/pluginname/lib/app/models ??????

Hi,
I 'm trying to make a plugin, and i have activerecord models that i
want to index them with sphinx.
when i run rake thinking_sphinx:index , i discovered that only models
in app/models were indexed.

this is what i put in one of my models stored in vendor/plugins/
pluginname/lib/app/models: