Hello, Chiming (Frank) Huang.
Thanks for your response.
this question is out of reach of the response support community. The best place to get help with SignableFile.bin is Microsoft Learn(English only), which aims to support more advanced users like you.
Here is a link to the forum where you can raise specific scenarios and share your idea to help solve the problem.
I won't be able to help you, but I'll leave that question open in case one of our amazing volunteers has ideas for you.
If there is anything not clear, please do not hesitate to let me know.
Best Regards,
Rick-MSFT | Microsoft Community Support Specialist