Disk discovery is usually done after WinPE/RE (the OS used on the Recovery Media) is up and running. I would try BOOTing up the Rescue Media first then plugging in the external disk before you do anything else... it should work just fine.
The BOOTing up with the external disk plugged in sounds like a BiOS issue, not a Hasleo issue... like maybe that disk is marked BOOTable (Active) but has no real structure to BOOT up. You should be able to get around that by removing the BOOTability of that disk, or worst case, position it in the BiOS BOOT order as the last device to use.
The BOOTing up with the external disk plugged in sounds like a BiOS issue, not a Hasleo issue... like maybe that disk is marked BOOTable (Active) but has no real structure to BOOT up. You should be able to get around that by removing the BOOTability of that disk, or worst case, position it in the BiOS BOOT order as the last device to use.