We went out and got a Brew Belt yesterday to help raise the temperature - got it up to about 71-72 and immediately noticed some airlock activity restarting.
We grabbed an extra satchet of t-58 just in case it needs some yeast reintroduction but the guy at the LHBS was pretty confident (as you all are) that it was a temperature issue.
BTW, we initially pitched 2 vials of WLP500 (not the kit yeast) but didn't have time for a starter due to our schedules - we picked up the yeast the morning of a brew day because we found last minute that the kit yeast was NOT a Belgian strain (believe it was Nottingham, but can't remember exactly now).
On a somewhat unrelated note, the LHBS guy told us that we really shouldn't leave our fully fermented beers in a plastic fermenter, as the vessel itself is subject to some oxygen penetration through the side walls. I hadn't heard of this, and seemed contrary to what I seem to read most often know (long stints in the primary fermenter, even after fermentation is complete, is preferred if no reason to rack to a secondary) and took note that he was obviously in the business of "selling" those expensive glass carboys he seemed to be implying were "necessary" so I resisted, but made me at least go "hmmmmm".