No triggers visible for different user in information_schema.triggers

Hello,

I am using a postgres 7.4 dbms, a single database DB in the public 
scheme and two database users USER1 and USER2, both of them having 
superuser priviliges.

USER1 is owner of all tables in the database DB. I have defined triggers 
on some tables as user USER1, and all of them are shown in the 
information_schema.triggers view. USER2 also can create and drop these 
triggers, but does not see any entry in information_schema.triggers. The 
query

SELECT * FROM information_schema.triggers;

returns an empty result. I thought this is caused by a lack of 
priviliges, but USER1 as well as USER2 are superusers.

What is my fault?

Kind regards,
Oliver Brueck