What is the preferred way to include other/UX files to a sencha touch 2 app.

In app.js I have:

Code:
Ext.Loader.setPath({
'Ext': '../touch/src',   
'MyApp': 'app',    
'Ext.ux.touch.grid': 'ux/Ext.ux.touch.grid'
});

// in one of my panels i require the UX List...
requires: ['Ext.ux.touch.grid.List'],...
This works fine when I run in "dev" mode. But when I compile with Sencah Cmd(sencha app build production), I get Errors.

App structure:
/app.js
app/ux/Ext.ux.touch.grid/List

Getting the error:
Code:
com.sencha.exceptions.ExBuild: Failed to find any files for Ext.ux.touch.grid.List (x-app-build#273)   
runAppBuild (x-app-build:273)   [anonymous] (x-app-build:545)   x_app_build (x-app-build:543)   <script> (anonymous:1)

Any pointers are appreciated!