How about the callerID from the landline via the OBi110 box to an extension of the Asterisk box? Is the Asterisk box able to show the caller ID from the landline?
Tested using Mobile Phone to call Asterisk extension via OBi110 box. My IP Phone SPA942 with Asterisk extension shows OBi110 SP2 extension as the callerID instead of the real Mobile number.