How to fix ACCESS DENIED when printing PDFs using Adobe Reader and CreateProcess without disabling protected mode?

Question

I'm able to successfully print PDFs automatically to some printer using the following command line if I manually create the shell and execute that command. What additionally works is e.g. printing some PDf in Windows Explorer using the context menu of the PDF and the verb "print".

"C:\Program Files\Adobe\Acrobat DC\Acrobat\Acrobat.exe" /h /n /o /s /t "C:\Users\[...]\some.pdf" "SomePrinter"

What does NOT work is using the exact same command line in some custom WIN32-app with CreateProcess. While Adobe Reader starts and tries to read the file, shortly afterwards an error message is shown about that the file can't be opened because the access is denied. The important thing of course is that I'm starting my app which starts Adobe Reader using CreateProcess under the same user like when successfully printing from the shell manually. Using ProcMon I can additionally see that the correct PDF is accessed, to there's no problem with wrong paths or alike.

What resolves that issue is disabling the protected mode at sartup of Adobe Reader. BUT that shouldn't be necessary in theory, because things work when manually executed on the shell, using the context menu and as well when not using CreateProcess with some commandline, but ShellExecuteEx with the verb print instead. The problem simply is that Adobe Reader needs to print untrusted PDFs, so using protected mode makes sense. Additionally, my app is deployed to many different systems and I would like to avoid the adminitrative task of reconfiguring Adobe Reader to disable protected mode. The downside of the verb "print" and ShellExecuteEx is that I can't forward additional arguments.

Looking at ProcMon again, the behaviour of Adobe Reader seems to be pretty much the same up until a point where things not work anymore when using CreateProcess. In both cases an instance of Acrobat.exe is created, which afterwards spawns an additional instance of itself using LowIntegrity mode and some additional command line arguments:

"C:\Program Files\Adobe\Acrobat DC\Acrobat\Acrobat.exe" --type=renderer /prefetch:1  /h /n /o /s /t [...]

This looks to me like there's some recognition of interactive vs. non-interactive usage or alike and the former is allowed and the second denied. While my WIN32-app is 32 Bit and Adobe Reader 64, that doesn't seem to be the problem as well. I tested with a 32 Bit cmd.exe starting 64 Bit Adobe Reader and things work like expected.

The following is how I start processes, which works as expected for anything else than Adobe Reader:

STARTUPINFO         si;
PROCESS_INFORMATION pi;

ZeroMemory(&si, sizeof(si));
ZeroMemory(&pi, sizeof(pi));
si.cb = sizeof(si);

LOG4CXX_TRACE(logger, L"Beginn CreateProcess");
if (!CreateProcess( NULL, const_cast<_TCHAR*>(cmdLine.c_str()),
                    NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi))
{
    DWORD error = GetLastError();
    LOG4CXX_ERROR(logger, L"CreateProcess: GetLastError: " << error << L"; " << cmdLine);
    return Result(cmdLine.c_str(), error);
}
LOG4CXX_TRACE(logger, L"Ende CreateProcess");

Making the started command line more complex and e.g. add "cmd.exe", like when things are done manually, doesn't change a thing. In the end Adobe Reader is still denied access to the PDF for some reason:

"C:\WINDOWS\system32\cmd.exe" /C ""C:\Program Files\Adobe\Acrobat DC\Acrobat\Acrobat.exe" /h /n /o /s /t "\\?\C:\[...]\[...].pdf" "SomePrinter""

So, what do I need to do with "CreateProcess" to fix this?

Thanks!