Socket timeouts (probably)

Hi,

I have a really strange problem here. I've got two Fedora 2 machines -
one for the database and one for a Java application to be run. When a
transaction from the application is run against the database and the
network cable is unplugged (or the machine is shut down) the database
continues to hold the lock on the tables, which are used in the
transaction. The lock is released in about 10-12 minutes, which in my
case is not acceptable, because if another client starts a transaction
against these locked tables his UI ties his hands until the lock on
the tables is released and the transaction is complete.
I started a 'netstat -atp' on the database machine and it turned out
that the connection with the unplugged machine is still active (5
connections actually, because of the connection pooling). So I assumed
that the sockets are just hanging there until they timeout and then
the locks are released.
My questions are is my assumption right and if that's true is there
any way to set the postmaster's sockets timeout to for example 2
minutes.

I appreciate any help on solving this.

Best regards
Sergei Georgiev