[R] Any ideas on how to add a dotted line to a box plot to indicate a specific value?

[BJ]

Basically, i want to create a boxplot from population data, with a solid 
line for the median, and then a dotted line for a specific persons 
value. Is there a way to artificially introduce another line or mark of 
some kind in a box plot? Thanks again for all of yoru help. Hopefully 
soon I wont have to keep bugging you all. ~Erithid :-p