The material we use for our RoHS compliance boards are built to withstand these higher temperatures. Solderability of silver immersion boards (Can I use lead solder on silver boards and what temperature needs to be used) Our RoHS compliant silver immersion finished boards can be soldered with standard tin/lead solder at standard tin/lead temperatures or using RoHS compliant solder at the higher no lead soldering temperatures.
The above information was taken from RoHs and Immersion Silver Frequently Asked Questions page.