WD MyCloud combine storage with external storage

I have a 2 bay EX2 MyCloud and I found the 4 GB inbuilt storage rather limiting. Rather than swap out the 2 HDD, is it possible to plug in an external HDD and combine its storage into the RAID config of the NAS?

I read the manual and it mentions that the USB can be used for storage but I assume it will appear as a separate folder. Is it possible to integrate it into the RAID config?

It’s currently in RAID 0 config. That means I have 2x 4 GB HDD.

Hello,

Please refer to the following KBA article: My Cloud: RAID Online User Guide and Solutions