Thank you very much Rui.
I was in hurry because I'm working in a bank and on my master's degree thesys at the same time.
I know Matlab, but they want I use R to price a convertible bond (I can't get why...).
I read "An introduction to R" the last week-end and now I feel more confortable.
This is an help section and was not looking for a good telling-off but I'm sorry if I bothered somoone with my question.