Many applications such as e-commerce and electronic banking services are becoming very popular and needed for many of the daily Junctions. One of the main success factors of these services is their continuous availability. These services must be available without interruptions 24-hours a day 7-days a week. Most of these applications require integration with legacy systems. However, many of these legacy systems were designed to provide their services during specified periods of the day and suspend for the rest of the day for different reasons such as performing data backups and end-of-day processing. This paper proposes reliable and efficient middleware-based methods to increase the availability of integrations with legacy applications. Some methods utilizing concurrent processing and database replication are suggested to solve the scheduled legacy applications unavailability. This paper discusses the problem in details and describes the proposed solution for the case of electronic banking. A real-life implementation of the proposed solution was implemented at a bank resulting in the availability of the banking services being increased significantly.