Defining custom index content for smart search: Web Application

Hi, I have created a custom search index using the following instructions: http://devnet.kentico.com/docs/7_0/devguide/index.html?smart_search_defining_custom_index_content.htm When it comes to setting up the index in the site manager what assembly name should I use. Assembly name 'App_Code' is returning the following error 'App_Code class cannot be loaded because the OnGetCustomClass handler is not initialized.' . Assembly name 'CMSApp' produces a "Classname could not be found" error. What am I doing wrong in getting these things to tie together? Thanks in advance, Sam