The Live Access Server (LAS) is a Web based framework for visualizing and subsetting environmental data sets. The framework contains two servers -- a user interface server that controls the presentation of data to a user, and a data server that manages visualization and subsetting of data through connections to legacy data management and visualization software. The user interface has been customized for a number of different projects, and the data server has been integrated with several different legacy programs. This talk describes the techniques used for these customizations, including methods for changing the menus and maps presented by the user interface, and methods for integrating different legacy visualization programs into the LAS.