PS5000e shared between DMZ and Internal virtual servers

We would like to use our single PS5000e to provide services for our servers which are in the DMZ and internal network, with different volumes created for each (enabling CHAP, etc)    More specifically, we use VMware ESX 4.0, and and we'll use the VMware iSCSI initiator (so the virtual servers don't really see the SAN, just the virtual drives that VMware presents).

Is there any good documentation that discusses using a single SAN shared between DMZ and internal hosts, best security practices, etc?   Looking for discussion on whether this is common, and how we "sell" this configuration from a security standpoint.

Thanks.