Hi Bosmanmartin, Thanks for your post and welcome to the community! As noted in manual there is no exact code for Multi choice on the Universal remote, however on our other remotes there are codes, I can't guarantee this will work but please try 00879.
Please let me know if this helps.
Hector_B Community Support
I'm sorry to hear that. Third party devices will have different areas that we can't always cover. Here are some of the other remote codes, feel free to try them HERE for the SoundTouch 300 and HERE for additional Bose remote codes.