Multicast “SHOULD” be the FOG Master Node. Unless your NAS Box can install web and run UDP, it MUST be done with a different box.
That said, NAS’s have a lot of their own problems with FOG Beyond multicast. 1.2.0 just isn’t very friendly with them. I’ve made some strides with the issue’s most NAS’s tend to cause in FOG Trunk, but what you’re wanting to do (Multicast from a NAS) is still not something I would try.
First, as I stated earlier, the NAS would need to be it’s own node completely for it to work best. While many NAS box’s have a form of linux running them, I don’t think they have the utilities available to install UDP-Cast which would be needed.
Your best option would be to mount the NAS’s storage to a more appropriate system that has a FOG Server installed.
Second, if you go with the option to mount the NAS’s storage, the work is, most times, mounted from the network. Multicast just wouldn’t work very well because of how UDP works. UDP spams its packets out without caring who or what see’s them. This, typically, floods a network. As the NAS is network connected, it would also be spammed by these Packets. Essentially, this could cause a complete disconnect of the NAS’s shared filesystem, ultimately affecting the imaging you’re doing.
If you must use a NAS for storage I would highly staying away from Multicast.