In 

```
library(ggplot2)
library(reshape)
df <- as.data.frame(matrix(runif(9),3,3))
df$factor <- letters[1:3]
df.m <- melt(df)
ggplot(df.m, aes(variable, value)) +
  geom_boxplot() +
  facet_wrap(~factor)

```

i want to change the facet names. According to the ggplot2 tutorials, this is working:

```
new.lab <- as_labeller(c(a="A",b="B",c="C"))
ggplot(df.m, aes(variable, value)) +
  geom_boxplot() +
  facet_wrap(~factor, labeller=new.lab)

```

However, this is not:

```
new.lab <- as_labeller(c(a="A",b="B",c=expression(italic("C"))))
ggplot(df.m, aes(variable, value)) +
  geom_boxplot() +
  facet_wrap(~factor, labeller=new.lab)   

```

How can i get italics (or any other special symbol) in ggplot2 2.0 facets?