Ember.js: How to remove folders (.svn) from asset compilation

I am using Ember.js with ember-font-awesome. For some reasons I have to version control my project with svn what puts a .svn folder within every directory. When building the project, ember automatically compiles assets (uglify, minify, copy to appropriate directory). This works for assets within dependencies as ember-font-awesonme out of the box. Buit it fails when having a .svn folder within the ember-font-awesonme fonts directory. This is the error message: You must pass a file to 'app.import'. For directories specify them to the constructor under thetreesoption. First I really don't know where and how to specify directories to the constructor (maybe somehow in the ember-cli-build.js) ansd more important, I don't want to specify it to the constructor. Insteasd I want to exclude it from compilation process.

Would be very fine if someone had a solution for me.

Thanks in advance.