My WD mypassport cannot be unlocked when connected to MyCloud

Not had MyCloud for long, but its working well so far.
I had started to manually transfer files from a Mypassport hard-drive through the windows interface, but with the prospect of 600GB to do folder by folder I wanted to just connect the passport to the Mycloud, which I am pretty sure would work with some configuration.
Problem is whenever I disconnect passport from USB on PC, it password locks, so when it is connected to the Mycloud USB, I have no way of accessing the passport, or even the unlocker.
Can one got any ideas as to how I can do this?

Have you read the User Manual?

Try this and it comes from the My Cloud User Manual.

Overview When you attach a USB drive to the My Cloud device’s USB 3.0 expansion port, it becomes a network drive. Now the USB drive has the following capabilities:  When you connect an external USB drive such as a My Passport™, a memory stick, or a camera to the My Cloud device, you can access it with Windows Explorer or Mac Finder.  The USB drive can serve as a target for backups in WD SmartWare, Windows, or Time Machine.  You can map the drive as a user share drive (Windows) or an alias (Mac).  If a WD external drive has been locked, when it is attached to the My Cloud device, it maintains that security and can be unlocked or relocked using the Dashboard.  You can attach a powered USB hub to the external USB port and attach up to seven USB devices to the hub.

Suggest you read it if you haven’t. This is for the 2nd generation My Cloud. Which do you have?
https://www.wdc.com/content/dam/wdc/website/downloadable_assets/eng/user_manual/4779-705147.pdf

Thanks for this, I did indeed read the same (I also have the 3TB 2nd gen mycloud)
Unfortunately, its not working for me right now, I am running WDSmartware as the interface, which can see the passport when its connected to the PCs USB and unlocked, thats OK, but the idea was to connect the passport directly to the myclouds USB and access it through the various remote devices, separately from the new stuff thats going to be backed up on the mycloud (kind of keep old away from the new if you like).
Once its removed from the PC and hooked to the mycloud, it is no longer visible, either from explorer or smartware, I can only imagine this is because its password protected, but I simply cannot access it from any interface, explorer, smartware or mycloud dashboard!!
Just wondering if anyone knows why, or have a similar problem , or indeed a fix?

Regards
Andy

A locked USB driver will look like this,
If you don’t see this, then the My Cloud doesn’t recognize the USb drive or it just didn’t mount for some reason.