Berlin,
You will need to follow the instructions in the following post:
http://e2e.ti.com/support/development_tools/webench_design_center/f/234/t/36943.aspx
If you have a direct TI sales contact, you may also request an unencrypted model through that contact. Please remember that in some cases, an NDA may be required in order to obtain the unencrypted model.
Britt