FTP Client for automated secure backups, Window XP onwards

We have a clear understanding of what we would like this software to look and feel like. We do not have time to develop it in-house hence we are outsourcing. Our company offers remote off site backup. The aim is to have a lightweight software package installed onto a customers PC or server which once setup the customer will not need to look at again. all the files and directories that they choose will be automatically backed up as and when changes are made to them. everything uploaded will be encrypted and password protected meaning they and only they will be able to access them. file name and file type will be visable but everything else will require thier password to be inputted. the customer will also be able to restore/download using this new software and, if they choose, they can just enter thier password once to unprotect all the files they are downloading. the list below is not exhusted and we will be looking for the developer we hire to make suggestions and come up with new feature ideas. we understand that there are several opensource projects available for customising plus there are .net FTP classes available to buy. We hope to make use of these and save development time please make sensible bids and leave your comments and suggestions. Requirements: • Either VB.net or C++ to be used • Windows XP onwards & Windows 2003 onwards compatible. Possibly MAC compatible. • Long term relationship required to supply updates, fixes, new features etc etc, client side of this project if phase 1. Phase 2 will be server side. • Regular communication! Features: • Automated upload of selected files/folder and or scheduled uploads. • Detection of file changes which activates upload. • Automated password protection encrypted for all files/folders, maybe some sort of zip? • Multiple ports used • Proxy server settings. • Directory browsing on client machine and remote machine. • Usage counters, total sizes etc • Ability to right click any file on the client machine and add it to the upload list which means that file will be constantly checked for changes. • Auto resume function for dropped connections • Multiple revisions stored on server • Auto creation of correct file structure on server. • Detection of client machine name • Optimized for speed and security • the ability to ignore certain types of files extentions for example .dll's