The ImageMan.Net Twain components can be used in a WPF solution in Visual Studio with a couple of special steps:
1. Enter your registration key at the trial dialog, this is only required once.
2. Create the controls in your code progammatically, the controls cannot be added to the Visual Studio Toolbox in a WPF solution as they are Winforms controls and even if you add a Windows Forms Host control to your WPF page the Toolbox still only contains WPF controls.
3. Create a text file in your solution called licenses.licx and set the Build Action to Embedded Resource. Paste the following line into the file
DTI.ImageMan.Twain.TwainControl, DTI.ImageMan.Twain, Version=188.8.131.52, Culture=neutral, PublicKeyToken=3ff15c974c5defd8
Do a full rebuild of your application and that will embedd the license data into your application. Once this is done you can deploy the exe to a client machine and they will not see the trial dialog.