Description of problem: Whenever I try to select a disk image from a sheepdog pool, virt-manager makes a qcow2 image with the same name in my home folder. When adding manually with virsh and a .xml, it does work. After upgrading to virt-manager 1.4.0 (sid), I can see the added disk image as: "sheepdog:///image". When I use the Add New Virtual Hardware wizard and select the correct image from the pool (Manage...), the textbox just shows the image name. I can prepend this with sheepdog:/// to make it work. Unfortunately, this option is not available in the virt-inst wizard. So I have to customize, remove and re-add the image.
Sorry this never received a response. There's been a bunch of improvements to virt-manager network pool/vol handling since this was filed. I'm not sure if this particular issue was fixed though, but because it's been a while I'm closing this for now. If you or anyone can still reproduce with virt-manager 2.1.0, please reopen and provide full virt-manager --debug output when reproducing.