Sorry for being unclear.
I'm using composer and config.yml to load the files.
I also took a look yesterday at the bundle (first result), but for bootstrap 3.0 there was an easy way to configure, so i asked myself if there was also an easy way to do it with bootstrap 3.2.
I don't want to include the js and css files manually, want to let this be done by composer / Symfony.
This was the way it worked with bootstrap 3.0:
http://mossco.co.uk/symfony-2/symfony-2-and-bootstrap-3-assetic-config-and-base-html-template-file/
As the less is not supported / developed anymore, it doesnt work for 3.2 bootstrap.
Hope the question is now clearly enough. If theres any approach without the bundle you'd really help me.
If this is the easiest and most reliable way: https://github.com/braincrafted/bootstrap-bundle
i will use that bundle.