DBCENTURY

Hi, I have looked everywhere to understand how to use DBCENTURY. I looked at www.informix.com/informix/products/year2000.htm and found information. I then looked in the Informix Guide to SQL:Reference and found the syntax. It seems like I just have to set the DBCENTURY variable in the user profile and It should work. But Informix ignores it. Can somebody can give me a hint? Do I need to set something else? This is the way I set DBCENTURY: DBCENTURY=C;export DBCENTURY The system I use: AIX 4.1.5 SE 7.2