Storage Pools: Extending virtual disk after expanding Azure Disk

We host our Windows Server 2016 Virtual Machines on Azure and I am having a problem to expand one Virtual Disk on the Storage Pool after having expanded the disk on Azure.

The Virtual Disk is a simple 300GB. The Physical disk is an Azure 300GB (Premium SSD), as you can see in the image below.

I expanded the Azure disk to 400GB, but this change was not reflected in the physical disk on Storage Spaces. Instead, it mounts my old disk just as it was before, and present another 400GB disk with 100GB free space.

How can I expand my Virtual Disk to 400GB? Is it actually possible or I would have to add another 300GB disk and expand in 300GB increments due to the column size? Am I misusing Storage Spaces on this scenario and instead it should be just a simple volume on windows?

If you have a look at the docs for expanding disks in storage spaces it has this warning:

Not supported: resizing the underlying storage used by Storage Spaces Direct. If you are running Storage Spaces Direct in a virtualized storage environment, including in Azure, resizing or changing the characteristics of the storage devices used by the virtual machines isn't supported and will cause data to become inaccessible. Instead, follow the instructions in the Add servers or drives section to add additional capacity before extending volumes.

Given that, you need to create a new disk in Azure and then extend the pool to use that, rather than trying to expand the existing disk