Can't see how to create boot LUN for ESXi blade

Can anyone help with how to create a boot LUN on an EMC VNX5600 for a UCS blade? I've inherited a UCS/EMC system and while I have plenty of experience with UCS and with other SANs, I have almost no experience with EMC.

As far as I can tell, a host (i.e. blade) needs to be added to the SAN before LUNs can be provisioned for it. But this requires an OS, IP address, etc., on the host first...which I don't have because the blade has no local disk. It needs to have a boot LUN on the SAN so that I can install the OS...which I can't do because the host isn't added to the SAN.

You see my problem!

I'm sure I'm doing something wrong here so I'd really appreciate if someone could point me in the right direction.

Thanks.