Hi Tomas,
For my overland truck setup the idea is to 'ride' on a Public or Paid AP, broadcasting that to our own Hotspot around the truck. I prefer to have the Hotspot function as to have some level of control over the kid(s) with respect to data usage and time online.
After some reboots, swapping the SIM card, and having the prepaid connected to the Vodafoon network in an old Nokia. The data connection seems to be established using the prepaid card in installed the modem.
However, it looks to me that the WiFi connects to the router as AP and not as Hotspot. As I do not get the login screen when connecting. When connected the browser responds that I'm not connected to the internet trying to connect to a www address.
-R