The Gaia ubiquitous computing platform currently supports mobile devices through a thin client proxy architecture. Mobile devices run a lightweight proxy client written in J2ME to join an active space. While this approach allows a wide variety of devices to interact with active spaces, it lacks the ability to use device specific functionality. This problem is addressed by combining the J2ME client with a microserver, which is a bridge from the native language to J2ME. The microserver-proxy approach enables thin clients to fully access device-specific features while respecting security through a standard interface as Gaia services.