you could contact Nokia directly (they have a discussion forum.. you could try posting there ?)
i’ve read there that the 6680 is a Rel4, but it doesn’t say about NACC/PSI support. I believe that a MS can be partially compliant to a realease. For instance, the BSS release can be only “partially compliant” to a certain 3GPP release.
So to be sure, you should contact Nokia…