A method to perform system selection with a mobile station, comprising: invoking an overlay function configured to assist the mobile station in performing system selection based on a set of overlay parameters, wherein the set of overlay parameters comprises a system priority list specifying priority of various systems; determining if the set of overlay parameters specify that a higher priority system is to be acquired; and if so, initiating a scan to attempt to acquire a network of the higher priority system using a preference list for network selection corresponding to the higher priority system so that the network of the higher priority system is acquired based on the preference list, if the attempt to acquire the higher priority system is not successful, attempting to acquire a lower priority system, wherein the higher priority system comprises a home system and the lower priority system comprises a non-home system that is not the home system; else, if the set of overlay parameters do not specify that a higher priority system is to be acquired, attempting to acquire the lower priority system comprising first selecting a most preferred system selected from the system priority list, then after selecting the most preferred system, acquiring a network in the most preferred system, wherein the acquired network is selected from a corresponding network list that depends on the selected system, wherein after acquiring the lower priority system, determining if the set of overlay parameters specify that the mobile station is to perform a background scan for the higher priority system and, if so, periodically scanning for the higher priority system in an attempt to acquire the higher priority system. invoking an overlay function configured to assist the mobile station in performing system selection based on a set of overlay parameters, wherein the set of overlay parameters comprises a system priority list specifying priority of various systems; determining if the set of overlay parameters specify that a higher priority system is to be acquired; and if so, initiating a scan to attempt to acquire a network of the higher priority system using a preference list for network selection corresponding to the higher priority system so that the network of the higher priority system is acquired based on the preference list, if the attempt to acquire the higher priority system is not successful, attempting to acquire a lower priority system, wherein the higher priority system comprises a home system and the lower priority system comprises a non-home system that is not the home system; else, if the set of overlay parameters do not specify that a higher priority system is to be acquired, attempting to acquire the lower priority system comprising first selecting a most preferred system selected from the system priority list, then after selecting the most preferred system, acquiring a network in the most preferred system, wherein the acquired network is selected from a corresponding network list that depends on the selected system, wherein after acquiring the lower priority system, determining if the set of overlay parameters specify that the mobile station is to perform a background scan for the higher priority system and, if so, periodically scanning for the higher priority system in an attempt to acquire the higher priority system.