Table partitioning problem

Hello,
I have a problem with table partitioning because i have a foreign key 
applied on the partionned table and it throw a constraint violation 
error during inserts.
I saw on the manual 
(http://www.postgresql.org/docs/8.4/interactive/ddl-inherit.html caveats 
section) that it's a limitation due to postgrsql table inheritance 
select queries performance are really bad without partitionning and i'm 
looking for a workaround to this foreign key problem or another solution 
for improve performance for larges tables.

Thanks in advance for your responses