SHMEM settings under FreeBSD

I am trying to run postgres under 4.2-STABLE FreeBSD using a large amount
of shared memory, and am having problems finding the correct settings.

The box has 512MB or RAM, of which I would like for Postgres to use 400MB
for buffers and 32MB for sorting, which I determined would be:

-B 51200 (51200 pages * 8kb/page = 400*1024kb)
-S 32768 (since the value is in kb)

However, when starting I get the following error:

IpcMemoryCreate: shmget failed (Cannot allocate memory) key=5432001,
size=427022336, permission=600

I tried increasing the kern.ipc.shmmax to 427022336 and 457022336, but I
am stil unable to get postgres to start.

Any Ideas?

Thanks

Michael Fork - CCNA - MCP - A+
Network Support - Toledo Internet Access - Toledo Ohio