Hi Richard,
The lead free solder does indeed have a higher silver level and a considerably higher melting temperature than the usual silver-bearing leaded variety.
In addition to the preferred usage of silver, one of the other expressed concerns of Tek is the usage of excessive heat when working with the ceramic terminal strips.
I would think that so long as you use an appropriate wattage iron with good sized tip (ie with adequate thermal mass) you should be able to complete the soldering quickly without causing damage to the strip. Also, Tek has stated in their literature that for occasional repair work, regular tin/lead solder is acceptable.
Art
