Mobile Network Operators have invested massively into the roll-out of their UMTS or 3rd Generation Mobile Networks. Now they are changing their focus from infrastructure roll-out to the deployment of new attractive data and multimedia services in 3G networks. Within the Open Mobile Alliance (OMA) requirements for a future Mobile Service Architecture have been defined. We describe the Service Creation Environment developed at NEC's European Network Laboratories (NL-E) in collaboration with NEC's Mission Critical Business Operations Unit, meeting the requirements as set forth by the OMA. Key aspects of our SCE middleware platform are policy control and security technologies, helping application developers to tie OMA service enablers efficiently into new user friendly mobile services. With this technology, service providers can develop new communication services faster and open their network for new services developed by 3rd party service providers.