Have you tried being primitive about the ending, and just assigned it as two int32s? The first being clairvoyance and the second being a combo list-terminator/aug slot number?
Using the structure already found for SOF, taking the 0x00000001 to mean slot 1, since the item has aug slot #1 set, could work nicely. Wasteful, sure, but they might not have cared for a packet that is only sent rarely. (Support for that idea should be found in the fact that they are sending the majority of data as 32 bit ints, when they could just go for 16 bits as well. Live items have only started in on 4 digits for HP/Mana/End, lots of room left until a short isn't enough.)
The list terminator would work on the principle of a non-zero value meaning that there is item data following, which is mounted in the aug slot indicated. A zero would be the end of the list.
The clairvoyance at least should be easy to test, given that you've been able to inject the heroics above. (Side note, I never knew that they made heroic resists, those aren't actually used on live, as far as I know.)
If you're playing around with the fields, some ideas for what some of the header unknowns could be: power source charge, copy item (found on test, they just set a flag to disqualify items from being tradded, sold, used in quests, ...), inst_attuned, evo level (both max and current perhaps).
I'd play with them myself, but I don't have access to a set of SOF discs currently. I've been meaning to work on adapting a legacy version, but the additional format changes are a pain....
As a handy reference, an item ID for an item that actually uses the string field in the effect structure to override the name.
34158 - Fabled Ring of Flamewarding - Changes the name of the focus effect from Sothgar's Rancor to Focus of Flames, thus retaining the focus name of the non-fabled version but boosting the actual effect.
fabled item version
non-fabled item version
My apologies if this particular feature is already well handled, the structures just seem to hint at it not being the case.