My situation is like the one depicted here.https://wiki.mikrotik.com/wiki/Connecti ... ice_Access

Now I connected using the Mac address of the smartphone through which I bought the connection (the wlan interface uses the mac address of the smartphone). The problem is, I created a virtual AP to share the connection inside the flat, but the smartphone cannot connect to it because, well, the mac address of the smartphone confuses the virtual AP:

Is there a way saying "if someone connect with this mac address, please consider that he has this other mac address instead" ? Like a mapping.

The smartphone has the macA, but mikrotik uses internally the macB mapped to the macA (and the network)

No. You should have set this up (without the overriding MAC address) BEFORE you bought the service
so the MikroTik's MAC address would be registered by the provider. Or use a phone you don't normally use.

Just call ISP to ask for reregistering smartphone's MAC to router's one.

Ok, thanks for the info!