Thanks for the question. This should be possible. However, I tested printig html customer letter and client crashed. So this seems to be a bug. I will report it and push it to the development team.
I would like to know what BackgroundHALShouldPause does, and how to use it. While it's listed in the HAL Primitives report, it is not used in source code and it doesn't appear in the LMS HAL...
