Mac OS X shared_buffers not same as postgresql.conf file

Hello all, 

I am hoping someone can help me with 9.0.4 server on 8GB Mac w/Snow Leopard and shared_buffers configuration setting.  

I have shared_buffers in the config file set for 32 MB and pgAdmin reports a value of 32 MB, but pgAdmin also says the current value is 4096.  Can anyone point me to any docs about why the current value may be different than the config value?  Temp_buffers are the same way, config file 8MB, but current value in pgAdmin is 1024?

Thank you.
Neil