Hi Yuki,
Thank you very much for your help to report the false positive of SecureAPlus installer to Norton.
When you reported, we were trying to reproduce it, but we can't, so we are not able to report it to Norton. We are using English version of Norton. I'm not sure whether there is any different.
At the beginning when you reported about the tmp file we don't have idea what happened. After a while, we realized that it may be because when we want to do real time scanning of a file, we make a copy of it as a temp file. At that time it was in plain. In the latest release of SecureAPlus, version 3.3.2, we have encrypted this file. I'm sorry that I haven't updated you about this.
There is still one problem though. The solution that I mentioned above will work if you only use Universal AV to do real-time scanning. When you use ClamAV, it will also create that kind of temporary, which the copy of the file that it scanned, and the content is in plain. So when it is scanning a virus, Norton may also detect that the temp file created by ClamAV is a virus (because it is the plain copy of the file).