Incompatibility Postgres 7.1 - Postgres 7.3

Someone can help me ....

I have a compatibility problem between Postgres 7.1 - Postgres 7.3...
Guess !!! It's --- timestamptz ---

When I create a field with timestamp type... the new postgresql replace that
by
timestamptz.... I use phpPgAdmin, I don't know where is from the problem...

Simple example, If I execute that :
CREATE TABLE "statistic" (
"Id" int4 NOT NULL,
"DATE" timestamp);

I shall have that on the database:
CREATE TABLE "statistic" (
"Id" int4 NOT NULL,
"DATE" timestamptz);

Grrrrrr, =)

Helpsssssss, Areski