Widely used approach to increase data availability and fault tolerance in grid systems is the data replication. Most of the grid data management and data replication solutions deal purely with read-only data sets. There is a lack of the tools that enable the management of updatable grid database replicas. This work presents a set of services for the replica content synchronization, which are designed to support relational and XML data resources, provide the interoperability of heterogeneous systems and enable the utilization of proven methods for consistency handling to synchronize replicas in the heterogeneous grid environment. The main component of proposed system is the update propagation service that coordinates the functionality of other involved middleware services. We present the prototype implementation and summarize achieved results. The achievements include the empowerment of multiple legacy grid middleware components by increasing their availability and the tolerance to the faults.