When you say you can' see anything, are you looking on the console/telnet/webpage/Ridgeline...
What does it show you when you do the command: show ports no-refresh
Mine is a 24 port swtich. 1-28 with 4 ports shared between sfp and copper. When I look at the ports it shows ports 1-34 1-28 for the front (Again remember there are 4 shared ports) 29-30 are Not Present (NP) 31-34 show as Acitve (A) - these are the module
I'm using the same switch (mine is x460-24x) and same module in my network here at work and haven't had a problem, but I don't remember having to enable it.
Go to the console/telnet and type in : show version. The first line the command should show is the switch version/serial number/.... The second should show the module. The next few lines should show power supply info. If it doesn't show the module in show version then it might not be seated right or faulty.