Dear All,
Despite reports to the contrary I have the 3G Backup Internet connection working with the "White Fibre Swisscom router"
For reasons that I don't comprehend I did not get a 4G connection working, if this changes then I'll post further.
here are the English instructions:
https://majzel.blogspot.com/2014/11/swisscom-3g-lte-backup-internet.html
Regards Marcus Bennett & Agata