Using a custom script in Advanced Options of Registration System Options

Hi, I would like to know if the “use a custom script” option in the
Advanced Options dialog (for choosing SystemId/USB Id/etc… to be used in generating a registration key) can be used to set a fixed registration key for all copies of an HTMLExe app. ie this would act like a Global Password but one that provides a “Trial” mode.
PS My question shows a “similar to…” info block but the question there is answered as “please contact support by email”. I have tried that but have gotten no answer.

Actually, use this workaround:

• Create a restricted publication to have a Trial version of your ebook.
• Generate one registration key with a common user name or company name: for instance “Registered”.
  Thus, you’ll have the trial and a registration key which plays the role of a password.

The custom script would not be helpful to make a global password.