Hide 'WP Backery' (named before 'Visual Composer') Menu Item

It wasn't too intuitive, but I managed to fix it like this:

1. Go to Settings > Adminimize
2. Expand Menu Options and scroll all the way down until you see "Your Own Options slug"
3. Enter WP Backery/Visual Composer Item in the left box, and also enter vc-welcome in the right box
4. Click "Update options"
5. Expand the Menu Options again and scroll down to the same place. You will see, that at the end of the list a new option is added called "WP Backery/Visual Composer Item Custom"
6. Check the box under the desired user role
7. Click "Update Options"

Also helpful topic from wordpress.org forum.