How to find infotype mandatory fields?

Hi guys,

I am using function module HR_INFOTYPE_OPERATION to insert records on a certain infotype, but sometimes I get message "Fill in all required entry fields" E055. This is very vague and therefore I'm looking for an approach where I can enhance this message completing it with the field missing. Running the function module visible is not an option it must run in background.

To do this I am trying to get the mandatory fields of a certain infotype without success. I've seen this topic but it isn't returning the expected values.

Have you ever faced a similar issue?

Thanks in advance