Just an idea for a workaround:
-Include the VISA Install files as support files into your main install package.
-In the installer options you can start a program after installion, so it should be possible to start the VISA installation
-For the patch... maybe that might work with a script (.bat) file that you start for the installation and replacement ? But then you shouldn't reboot after Visa installation and do this reboot in the script.
Henrik
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'