[igraph] Can we plot the edges of a digraph separately as arcs?

[davidr]

If I have a directed graph and want to label or color the two edges
between two vertices differently, how can I make them arcs?

example
Take your g from graph.data.frame and add an edge
> g <- add.edges(g, c(0,1), attr=list(same.dept=FALSE, friendship=2,
advice=1))
> E(g)$label <- E(g)$advice
> plot(g)

I would like to have different widths or colors for the two edges
between A and B.
Is it possible to show them separately?

Thanks in advance,
David L. Reiner