Francesco,
I haven't really considered SYS/BIOS support in my first message so you haven't misunderstood anything. The next step would be to make changes in SYS/BIOS to recognize your target as compatible with ti.targets.arm.elf.A8Fnv. SYS/BIOS is delivered with all sources, so you can change it and rebuild it. To overcome the current error, you can add the following line to ti/sysbios/family/Settings.xs, right after the line 59:
"ti.targets.arm.elf.A8Fnv" : "arm", // line 59
"SystemElectronics.targets.CPU2E000100" : "arm", // new line
There are probably a couple of other places where you would have to make a change. Also, I need to mention that adding support for a new target, which is the same as a supported one, is not normally done or tested.
However, after reading again your initial post I would like to ask is the addition of one library the only difference between A8Fnv target and your target? It's possible that we can avoid adding a new target. What do you deliver to your customers, a RTSC target package or some other kind of package? Do they just choose your target in config.bld or in CCS, or there is something in the config script that your customers need to do?