Using index with order desc

Using pg 7.2.1

If I have a simple table transfer

company_id int,
module character(2)
otherfields ...

and an index
CREATE INDEX transfer_5 on transfer(company_id,module);

with the query

explain select * from transfer where company_id=1012 order by
company_id,module desc;

I get ..

NOTICE: QUERY PLAN:

Sort (cost=462.74..462.74 rows=117 width=176)
-> Index Scan using transfer_5 on transfer (cost=0.00..458.71
rows=117 width=176)

Other info ..

select count(*) from transfer where company_id=1012;
count
-------
5264
(1 row)

import=# select count(*) from transfer;
count
-------
23481
(1 row)

Why does it have to sort it? The desc is at the end and the first
argument is constant. Is there some way I can force postgres to read the
index backwards and save the sort step?