*** Update ***
As promised, here is a working update:
1: Installed the HP P410 adapter in my DL 380 G5 (officially the P410 is not supported in the G5 BUT it works without issue)
2. For sh*ts and grins, I updated the firmware of the controller before connecting or doing anything else
3. In order to adapt the P410 connector to the DL380 G5 backplane, I ordered two of these from monoprice: http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10254&cs_id=1025408&p_id=8191&seq=1&format=2
4. Booted into the P410 controller (F8 after the iLO F8 message) to ensure my array was recognized
Caveats
ESXi 5.1 recognized that the array was 3TB in the storage configuration properties in the host however it would not let me extend the VMFS past the original 1.8 TB size.
Since I was able to at least get into the array I migrated the virtual hosts to a second ESXi box (using vCenter). Since this was a test machine in a lab I didn't migrate the virtual hosts before initially modifying/extending the array because if I lost everything it wouldn't be a big deal. Now that I was able to get into the array using the P410 controller I went ahead and moved the virtual hosts to a second box.
Once everything was migrated, I re-created the array: 2.7 TB of useable space. 