The invention relates to a method in a Mobility Management Entity (10,11) for handling a setup of an S1 Application Protocol signalling connection between a first radio base station and the Mobility Management Entity (10,11) in a Long Term Evolution radio communications network. The Mobility Management Entity (10,11) receives an S1 Setup Request message from the first radio base station (12). Furthermore, the Mobility Management Entity (10,11) sends an S1 Setup Response message to the first radio base station (12) enabling the first radio base station to handle the setup of the S1 Application Protocol signalling connection. The S1 Setup Response message comprises an indication of at least one supported tracking area code of a tracking area, which tracking area is served by the Mobility Management Entity (10,11).