PDU / PSU enhancements

The datacenter / rack view of 9.3 is really great, but I would suggest some enhancements regarding the power and PDU management:
For what I experience, the relation is as following:

Wall Power Outlet(s) <---> PDU Inlet(s) | PDU Outlet(s) <---> PSU Inlets (Power Supply Inlet(s) of Computers/Monitors/Network Devices, etc.

Currently there seems to be no connection between the Rack PDUs and Equipment PSU possible.

So here my ideas:

Create types Inlets and Outles, add them to PDU/PSU types and make connections between them possible: this should be roughly equivalent to the network 'Ethernet port' type.

And some minor other issues with the current implementation:

1) Plug = Outlet? And what does the 'Number' characteristic of a PDU plug mean?

2) It is not possible to add external links to PDUs