Transaction execution in mobile environments needs to be flexible, not only to support typical mobile computing characteristics, like movement, disconnections and limited resources, but also to support the variety of transactional properties that might be required by different applications. This paper presents an approach for flexible transaction processing in mobile applications, and describes an adaptive middleware for mobile transaction services (MobileTSe), that makes transaction services with different properties available on the mobile unit. We suggest a solution with transaction service discovery and control using UPnP.