How to save the OEM partition when installing ESXi?

My Dell PowerEdge has a preinstalled disk with an "OEM partition".

In the included documentation I could not find what is on this partition.

Now, when installing ESXi 5.1 from a CD, it detects that something is on the HDD and prompts to delete it.

Is it possible to skip deletion of this partition and tell the ESXi setup to just leave it in place?

Thanks,

Pavel