Thanks for the replies, I'm using postgres since 8.3 and didn't notice at the time of 9.0 release the change in the syntax, as the old syntax still works, every time I read the current documentation I didn't notice that I was using it wrong.
I agree with Tom Lane about leaving it alone.
Another question, I don't know if I should ask it here, why FORCE_NOT_NULL and FORCE_NULL doesn't allow * as list of columns as FORCE_QUOTE?