How to create an image with an additional data disk?

We are transitioning our existing imaging process to Azure Image Builder, but some of our images require a data disk to be included in the image. Is there a way to do so via Image Builder, or any plans to include this functionality?

As far as I can tell, the best workaround currently would be to distribute to a VHD, create an image using that VHD as the OS disk and specify a data disk (created separately), and then use that to create an image gallery version - unless there's a better way I'm not aware of?

Thanks for your help!