When a mobile station (MS) seeks access to a public land mobile network (PLMN) via an unlicensed or generic access networks (GAN) it first registers with a default GAN. If the default GAN is unable to serve the MS at its current location, it redirects the MS to other GANs serving the same of different PLMNs. However, when using the existing registration and redirection process, an MS has no means of knowing what services are provided by a specific combination of GAN and PLMN. In accordance with the present invention this is achieved by indicating for each PLMN and serving GANC an operation mode supported by the GANC. This operation mode being indicative of the interface used for communication between the GANC and PLMN it serves.