multinomial logistic regression with prior probability

Hi,

Is there a way to specify proior probability in
multinom()? The function has a weight option for
individual cases, but I would like to specify prior
probability for each category of the response
variable, just like what lda() does. My data have
categorical independent variables, so I think lda() is
not suitable. Or are there other R package/function
that can do the work?

Thanks