Instant update

Hi All,

Can a WSUS perform a instant update? I used to update critical patches
from Microsoft Windowsupdates or our indoor SUS server before deliver
to my client.
But when i upgraded to WSUS, I couldn't do it at all. My WSUS server
able to perform update to those machines in OU, which means our own
machines.
How to update directly to customer's machines without joining domain?
Is there a registry key to alter?
I could appreciate if someone can help me.

Thanks,
Alan Lim