Dynamic Folder Creation when Backing up to Azure BLOB Storage
I haven't seen any OOTB way to do this. I've had similar issues with backing up to Azure BLOB, though, (it can't handle stripes) so I generally have used PowerShell to fill in the gaps:


Perform your backup to disk
Use PowerShell + AZCopy to upload files to Azure Blob using Ola's default directory structure on your local disk. 


I usually wrap both these into a SQL Agent job for backup and have had good results.