Auto-compile and live-reload sass

I would like to have auto-compile and live-reload when i work with sass. I use vaadin in a maven project.
For that i used gulp plugins to have sass auto-compile and live reload.
The problem that i get an error during compilation because the compiler can not find the valo.scss file imported in mytheme.scss inculded to have the default vaadin design.
@import "../valo/valo.scss";

I can compile with gulp other files or when i delete this line but i can not when it's included. When i clean and install the hole project i didn't get this error and modifications will be overwritten. I think it would be generated some how.
How can i skip this error or have auto-compile and live-reload using vaadin compiler?
 

copy these themes to your maven project, and you can use gulp to auto-compile.
cp https://github.com/vaadin/vaadin/tree/master/WebContent/VAADIN/themes to  src/main/webapp/VAADIN/themes/

Thank! It works !
Is there any other solution not to get the hole vaadin sass code in my project ? 
I have a problem when i would like to install the hole project, it doesn't find some sass files.

It doesn't work for example for some icons in riuchtext