Add custom .js and .css to backend

I was trying to add some design too the configuration of the modules in the back of the site. I thought taht similiar to the template I could add to your FC MODULE something like: <filename>newdesign.xml</filename>
in: /modules/fcmoduule/mod_flexicontent.xml

But I have 2 problems 1 is that I cant load the file and the other is taht I only want it to be loaded in the backend. Any ideas?

This could be done via via a custom form field element that loads that will be added to the mod_flexicontent.xml

inside it's display function the required JS/CSS files could be loaded

you need custom CSS ?
custom JS too why?

I found that trick but it very hard. But i think I can manage to do it, slowwwwwwwly.

After so many struggle I decided to create a new MENU module. All menus is Joomla are paid or suck.

I want vertical menu, horizontal menu, add query strings, add anchors, publish date and unpublish date.

All of this is done already. Now I am creating the templates and configurations.

I wanted to add a more visual design appeal. Nothing special. Wanted to add a .css and a .js file so I can change the design and add a few jquery plugins