I have created a sharepoint solution, a publishing site, containing masterpages, page templates, webparts and list definitions in Visual Studio - this solutions has been deployed on a production-server and a complete homepage has been build based on the solution.

Now I need to update the design of the homepage so I have edited my page templates, list definitions and one webpart (a webpart based on an XML-definition given from Sharepoint Designer showing data fra a list). If I deploy this updated solution to a test-server, create a site collection and some pages I can see that my design is as desired.

To test the new design with the existing homepage I have received an export-file from the production-server and if I import this to the nemly created site collection on my test-server I would expect to see all content from the production site with the new design. I do get all the content but with the old design nor my webpart is updated - but my lists are updated, and if i creates a new page or site this also gets the old design.

What am I missing here?