SQL & PL/SQL

Hi

I want to join two tables using full outer join with multiple condition but facing problem doing so. The query is like the following sample query.

select a.unq_id,a.col1,a.col2,b.col4
from
((select unq_id,col1, col2 from tab 1) a
full outer join
(select unq_id,col3,col4 from tab 2) b
on a.unq_id=b.unq_id
and a.col1=b.col1);

While serching on the net found the following link
http://www.nyoug.org/Presentations/2002/9ijoin.PDF
saying outer join can't be combined with other condition using OR ( is it true forboolean operators) .

If so how to write my query? multiple unions ?

Please suggest.
Best Regards
Rajib.