Hi Florian,
I have configured cell phone number as username at one of our customer site:
- Disable the "visitor_phone" field at the registration page.
- Add "username" field and change its label as "Phone Number"
- Inside this username field, select "NwaSmsIsValidPhoneNumber" as validator and "NwaNormalizePhoneNumber" as conversion.
- Finally under the SMS receipt tab, select username at Phone Number Field.