[R] Simultaneous logit/probit models

[Min Zou]

Dear R Users,
 
I'm currently working on simultaneous multinomial models and wonder whether R has any package that can estimate such models. 
 
I've got a survey dataset that contains 2,000 individuals and one of the survey questions asked the respondents to chose two main reasons to work out of eight options (e.g., pay, pepople, to use abilities, etc.) . Now I'd like to model the responses using simultaneous logit/probit models. To my knowledge, LIMDEP (authored by Greene) can handle these models. As I know little about LIMDEP, I wonder if R has any package designed for these models. 
 
I have searched the R archive but haven't got any clue. Any suggestions?
 
Thanks,
 
Min
 
-------------------------
Sociology Dept.
Oxford University