I am working in a Windows 7 64bit machine, with ExtJS 4.1.2a and CMD v3

I have just generated a new application:

generate app -p D:\development\git\ExtJS4\Core\webapp\src\main\webapp\javascript\test - n testapp
then I go to the sass folder of the generated application
cd D:\development\git\ExtJS4\Core\webapp\src\main\webapp\javascript\test\resources\sass\default
this is my config.rb (only changed the output_style and the environment)

# Get the directory that this configuration file exists in
dir = File.dirname(__FILE__)
$ext_path = File.join(dir, '..', '..', '..', 'ext')

# Load the extjs framework automatically.
load File.join($ext_path, 'resources', 'themes')

# Compass configurations
sass_path = dir
css_path = File.join(dir, "..", "css")

# Require any additional compass plugins here.
images_dir = File.join(dir, "..", "images")
output_style = :expanded
environment = :development
I run

compass compile
It compiles my css file correctly, no warnings or anything.

Then I add the following in the app.scss taken from the Theming Guide in http://docs.sencha.com/ext-js/4-1/#!/guide/theming

@import 'compass';
@import 'ext4/default/all';

// Your custom code goes here...

@include extjs-panel-ui(
    'testapp', //changed to my own one, as some other colors down there...

    $ui-header-font-size: 12px,
    $ui-header-font-weight: bold,
    $ui-header-color: white,
    $ui-header-background-color: red,
    $ui-header-background-gradient: null,

    $ui-border-color: black,
    $ui-border-radius: 4px,
    $ui-body-background-color: #fff,
    $ui-body-font-size: 14px
I have a definition of panel like this:

    extend : 'Ext.panel.Panel',
    alias : 'widget.app-panel',
    ui : 'testapp',
    //more code here...
then I run again

compass compile
Output of the command:

WARNING: @theme-background-image: Theme image not found:
         on line 18 of 
And the same for several images (actually one warning per image in that folder).

The folder paths are correct but the image names are not: panel-header-testapp-collapsed-left-sides.gif does not exist but panel-header-default-collapsed-left-sides.gif does.
So the name of my application is not correctly added to the files, or they are not correctly copied with the correct name of who knows what is going there but the images are not generated, the styles they are (so I can see the red header and so on)

Also in the generated css file I can see lines like this:

/* line 168, ../../../ext/resources/themes/stylesheets/ext4/default/mixins/_frame.scss */
.x-nbr .x-panel-header-default-framed-top-ml,
.x-nbr .x-panel-header-default-framed-top-mr {
  zoom: 1;
  background-image: url('D:/development/git/ExtJS4/Core/webapp/src/main/webapp/javascript/test/resources/sass/default/../../../ext/resources/themes/images/default/panel-header/panel-header-default-framed-top-sides.gif');
  background-position: 0 0;
which is really wrong, browser does not find that images, they should be relative to the server, not to the file system, is there any configuration setting for this?

So two questions here:

1) What I am missing to get the images correctly "pathed" when I compile?
2) How can I tell the compiler to make the path relative to the css folder and not absolute related to the File System?

Any help is very appreciated.