triggers to foreign keys

If one has upgraded postgres from 7.1.2 to 7.3.1,
how does one convert all the triggers that represent
7.1.2 foreign keys to actual foreign keys.

What I really want to have, is that when I dump the new
upgraded database, that the tables will be dumped with the
original "foreign key" syntax as they were created initially on
7.1.2, and not a bunch of triggers.

My problem is that programs like Visio don't see triggers
properly as entity relationships when drawing reverse engineered table
ERD's.

It works 100% when the table is created in 7.3.1
with the appropriate foreign key syntax.

Will appreciate any help