A shared memory issue

[SysProg]

Hello,
Im using RH AS 3 U2 with 4 GB RAM which has been configured for Oracle DB.
As part of the configuration I added the following lines into
/etc/sysctl.conf:
<snip>
kernel.sem= 250 3200 100 150
kernel.shmmax= 2147483647
kernel.shmmni= 4096
kernel.shmall= 2097152
</snip>

But after doing `sysctl -p` and/or reboot I see (using /proc/meminfo) that
my shared memory allocation is equal to zero:
<snip from /proc/meminfo>
MemShared:		0 kB
</snip>

I don't have this situation in my RH AS 2.1 servers (the MemShared seemed to
be right).

So, is this a behavior of RH AS 3, or I missed something in the
configuration file?

Thanks in advance,
Sysprog