Implementing cascading deletes on an existing table

Hi all,

Im trying to find out the best way to implement cascading deletes on an
existing table.  I have this:

create table fe_custom_set_card(
 custom_set_id int4  references fe_custom_set(custom_set_id) on delete
cascade,
 card_id int4 references fe_card(card_id),
 card_sequence int2,
 category text,
 primary key(custom_set_id, card_id)
);

and I want to implement this:

create table fe_custom_set_card(
 custom_set_id int4  references fe_custom_set(custom_set_id) on delete
cascade,
 card_id int4 references fe_card(card_id) on delete cascade,
 card_sequence int2,
 category text,
 primary key(custom_set_id, card_id)
);

How do I go about making this transition?  Dump the data, drop the
table, recreate it and load the data?