How does O_prog_1, which is a single value in the HMI(?), comprise (get created from) %R02435 and %R02436, which are two values from the PLC?
Could you instead get the two 16-bit signed integer values for %R02435 adn %R02436 from the PLC into two integers in the HMI? Then it should be trivial to combine them into a single 32-bit signed integer using VBScript in the HMI.
The answer to your first question is: correct.
to your second question: I will try the second question tomorrow. I do think it is possible. that's exactly what emerson's support said.