Some time ago, we were tasked with a project to come in and replace a customer's old Mainframe system with a new intranet ASP.NET solution using SQL Server as the back end. Part of this was a re-engineering of the business as well - essentially, as we change the system, we were to be thinking of how we can better do business.
So, the first task was to come in and do the logical and then physical data models. The customer was in on these dicussions and had complete sign off. The next phase was to actually do the design and building of each module. Well, to make a long story short, the programming has been done and we are now into parallel testing of the system. Things are going wonderful for most of the modules so far - Except One.
We have one system where - if you would only let the business users see the application and reports, all would be well. It works with the new integrated workflow and automates previously manual processes and performs great per the specifications. Parallel testing has uncovered a few issues though with the migrated legacy data. The builders of the legacy system are having a very hard time understanding the new schema and business process, therefore, they are having a very hard time understanding how to take the legacy data and put it into the new schema. Because of this, they are calling meetings of the business users and stakeholders and telling them that the new system doesn't provide data that the old system did (when it really does) - this does make the new system look bad.
This is frustrating, to say the least. The new system works great, and provides everything they need and wanted, and if not for the inability of the IT staff to fill in the new tables with the old data, the business users would be happy with the new features and functionality.
I'm asking for suggestions for how to handle this. Because of some political moves, the new "architect" has no idea of how the system works, and cannot fully understand the ramifications of the changes the IT staff is requesting. The IT staff wants some fundamental changes to the system, which are essentially un-necessary and actually are a bad design - but they ARE the customer.