Hi,
Working on the assumption the Front Office is also a web application designed for the iPad you need to look at a HTML5 features supported by Safari within iOS called Cache Manifest and WebSQL.
Cache manifest will instruct the iPad to download all the website components required to operate in an offline capacity. Once it's finished loading for the first time you can put the device in aeroplane mode and the website will still works.
You can the use WebSQL as local storage. This is an in browser implementation of SQL Lite which can be used to store information within the client for recall at a later date.
Web SQL
HTML5 - Web SQL Database[
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Cache Manifest
A beginner's guide to using the application cache[
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Other points to consider are that the approach needed for a cache manifest application to that of a tradition web application are very different. With an offline web application you can't rely on the ASP.Net framework for doing most of the work. Data driven content creation must be done using JavaScript. With server side communication done via AJAX. Alot of the Chrome apps work in this way. The applications are written in HTML and JavaScript. The content is downloaded and cached when it is first loaded. It is then available offline. WebSQL is used for local storage, AJAX is used for server communications with error handling to manage when offline.