Coercing compound types to use generic ROW comparison operators

I am storing a rowtype that keeps the primary key column(s) of another
table.  E.g.,

 create table point (x int, y int, stuff text, primary key
(x, y));

then, think:

 create type point_pk as (x int, y int).

When I go to compare point_pks against one another I get errors about
missing comparison operators.

HOWEVER, I can do this no problem:

 select row(1,2)=row(2,3);

I would REALLY like to be able to use the generic row comparison
functions, which, as detailed in the manual, are equivalent to
comparing elements left-to-right.

Is there a way I can convince my custom composite data type (point_pk)
to use the row-wise comparison functions, so that I don't have to
hackishly rewrite the comparison algorithm for each composite type?

Using 8.1.5.

Thanks,

Randall

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Randall Lucas       Tercent, Inc.       DF93EAD1