@MartinS_2809254 Really not sure what you mean here.
You change the APN on a device to mob.asm.net on a one-off basis. If you are not getting data while roaming in the EU, then it may be that you do not have a signal. You should try setting network to manual and try each one you see to find a decent signal.
If you are roaming outside the EU, then you need credit to pay for all data usage but otherwise same thing applies as above.
