In version 2.6.6, you'll want to be in either "Title Only Extraction" or "Title - Chapter Extraction" mode. Click the "D" button (stands for demux), then click "Streams" button. That will slide a sidebar out of the window which gives you the options of which streams to choose. Only check the ones you want to extract. This will give you only what you want. It's in the manual, but it's not obvious when you're in the program.