I am using the USA version and I don't see it in the parameters list either. It is available in the schedules parameters and the custom properties list. I would suggest to just create a custom property or expression and map that to IFC.
Thank you Yves for your participation. I should point out that I had previously tested all possible surface values but none seemed to correspond. The targeted value in Yves' post results in a result of 0.00m2 whatever the zone area.
My first test had been carried out from AC22 and this property is indeed not operational. However since AC23, 24, 25 and 26. Yves was right ! Being used to performing this task with more recent versions, I had never noticed any malfunction on AC22. An old and obsolete problem !