Case-sensitive problem

Hi

I am trying to migrate MS SQL 6.5 database server to the postgresql
database )7.1). I have my program made in Power Builder and this
program is working without problems with MS SQL server. But when I
tried to change the database to the PostgreSQL I received following
errors:
1. The program(Power Builder) is not recognizing more big and small
letters (case sensitivity).
2. There is also problem with spaces ,with that is also having
PosgreSQL problems.

How can I fix that problem with letters? Is there any special way how
to build PostgreSQL ,so it is working well with PowerBuilder and
especially with small and big letters.

The PostgreSQL is running on Linux and PowerBuilder on Windows.

Thanks for all your answers