Predicate pushdown through a linked server

In sql server
create view db2ravi as select * from Openquery(hellodb2, 'select * from proj');
select * from db2ravi where pnum=P1"
but in the db2 server it is executing only select * from proj in place of select * from proj where pnum=P1
The above behaviour is same in Informix as well

Thanks in advance.