API: How to create a volume for qemu/kvm?

Hello,
I found official proxmox api docs (http://pve.proxmox.com/pve2-api-doc/) to be completely unclear on how to create a qcow/raw volume for qemu/kvm VM and assign one to it (or how to specify that a volume should be created on VM creation) and how to specify extra options for this volume (read/write limits),
Could someone explain please?

Thanks