Pure Tin terminations can be mitigated for components with solder terminations less than .030" in height from the PCB, by using 6 mil stencil with Sn63/pb37 solder paste. That's the simple story for our customers that require it. Beyond that height we either have the components solder dipped in advance of placement, or we touch up afterwards to assure no pure tin terminations exists.
These are guidelines issued to us by some of our higher end customers...
(http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=66236)