Using Dell OME to check for firmware updates

I was looking for a way to check for any available firmware updates for my servers without rebooting into the lifecycle controller and came across OME.  I have a lab setup so I can make sure I have everything working and know how to properly use it before I deploy it in production.  The lab setup is as follows:

PowerEdge 1950 with iDRAC5

PowerEdge R515 with iDRAC6

The 1950 and R515 have ESXi 6.5 installed.  The 1950 is running a Server 2012 VM acting as a domain controller and DNS server.  The R515 has no guests.  Both iDRACs and ESXi hosts have their DNS set to the Server 2012 DNS server and have hostnames assigned, as well as static DNS records.  I have OME installed on the Server 2012 guest.  Both ESXi hosts have the OMSA VIB for ESXi 6.x.

After configuring the discovery ranges, it can see the ESXi hosts but it won't see the iDRACs and, as a result, won't show the list of current firmware versions and available firmware versions.  For the ESXi hosts, I have it setup to use WS-MAN and SNMP, and for the iDRACs I have it setup to use WS-MAN for out-of-band.  Am I doing something wrong or missing a step?  Is there maybe an easier way to get this information?