OK, I'll enter this in case anybody ever reads this....
I have determined that the 3ware 9650SE software logs every instance of battery charging, even if it is charging for a second or two only. I have also determined that the slightest amount of battery discharge will trigger a charge action log event at the earliest opportunity.
Accordingly, if there is no battery charging after a period of "Suspend", then it is safe to presume that there was no battery discharge occurring during the suspend, and that, by implication, the 3ware 9650SE card had power during the entire suspension.
That is in fact what I found with two test periods of 12-hour suspend: there was no battery discharge evident and therefore it seems, for this MB and card at least, that power is in fact maintained to the card during suspend.