We mention how to do this in passing in the "What does the "client.wyc" file contain?" frequently asked question.
The process is something like this:
- Change anything that's in client.wyc (in your case the download sites)
- Click the "Build wyUpdate" button.
- Add the generated "client.wyc" file to your new version (both within your wyBuild project and within your installer).
- Make sure every new version in wyBuild includes the latest client.wyc file (ditto for your installers).
We're going to make this easier in the future (that is, wyBuild will automatically do this for you).
Tell me if this helps.