[R] Simple decision trees - rpart?

[Per Bak]

Hi,

I'm looking for help on how to use R for making simple decision trees to 
calculate EMV's, in a manner similar to the method applied in the 
PrecisionTree add-in for Excel. Say, what is the optimal action, if:

Action 1 
 - could have two out comes with probabilities of 60% and 40% and associated 
values of 100 and 20

Action 2
- could have three out comes with probabilities of 30%, 60% and 10% with 
values of 200, 30 and -50

I have tried to read up on the 'rpart' functionality, but I think I might be 
looking in the wrong direction. I would also like to work with continuous 
distribution functions within the tree.

Can anyone point me in the right direction?

Kind regards,

Per