Windows 7 - Set default TWAIN scanner

I had a Epson scanner installed in Windows 7. Then I installed another scanner, a fujitsu, and unplugged the first one.

When working with an application wich used TWAIN drivers in order to connect to the scanner, the default device was the Epson. Specifically, the application used the Dynamsoft Dynamic Web TWAIN plugin.

The default TWAIN device is stored in Windows registry, under the following key:
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\TWAIN

In the referenced folder, C:\Windows\twain_32, I had the following structure:

The solution was just to select the fujitsu ds file, and update the registry entry.