To get straight to the point, is the germination of impatiens walleriana inhibited by high temperatures? (~90F)

I live in the tropics where that is pretty much the average (indoor!) temprature. I have had good success rates with other annuals using the baggie method (with coffee filters and placed under "daylight" T5 tubes when necessary), but just can't seem to get any germination at all from the impatiens seeds. I started with a packet of "Dazzler" from an eBay seller, and when none germinated after more than a week, I assumed that it was a bad batch. Tried some "Baby Pink" from a different seller, but still nothing!

I know certain annuals such as petunias do not thrive in hot temperatures, but I was hoping to get at least *some* germination from these impatiens seeds to try my luck at potting them outside ;-)