mPCIe card not recognised in Embed box 5000

Hi,

We have some integrated Embedded 5000 systems in our lab that we need to upgrade with via some mini-PCIe cards. The machines do not seem to enable them through, it does not appear in bios system info and neither in OS.

Since the machines aren't the newest and out of official support, I figured here would be the best place to ask.
The cards are tested fully functional in other machines. I've tested one of the machines with a wireless card thats in the factory optional list, which works no problemo.

Is there some security setting or jumper that's needs changing? Or is this bios whitelisting? Even though the latter would be absolutely outrageous for a professional device of this calibre...

Thanks in advance