sim fails to handle missing values

[izahn]

Missing values cause sim to produce no output

library(Zelig)
data(turnout)
tmp <- turnout
z.out <- zelig(educate ~ race + vote, model = "ls", data = tmp)
x.out <- setx(z.out)
s.out <- sim(z.out, x=x.out)
summary(s.out) #works

tmp[1, "vote"] <- NA
z.out <- zelig(educate ~ race + vote, model = "ls", data = tmp)
x.out <- setx(z.out)
s.out <- sim(z.out, x=x.out) 
summary(s.out) # fails to produce output

[SolomonMg]

The problem is actually in setx()