You can also do it by specifying the `rpar` arguments exactly as they appear when you run the regular` mlogit()` command.  So for your example:

    rpar = list("A:scan.id"="n", "C:scan.id"="n", ...)

where they named list must be quoted because of the ":" (I think, it may just be for "(", but it works with quotes either way) -- see footnote 20 p. 24 of documentation.  Also see 1st paragraph of p.26 of documentation about having to list the entire name of individual specific coefficients.  I had a similar problem when trying to just use scan.id but it stated working when I started putting the `A:scan.id = ` argument instead.  I believe you can do this with your data, as long as you set `panel=F` which I think is the only time the `id.var=scan.id` is invoked for multiple observation on the same person.  If you do in fact have a panel, then don't use that variable and use the other variables you want to simulate as normal or another distribution.  I'd also recommend using `halton=NA` argument if you have a large dataset as it speeds up the simulation significantly.