[racket] What #lang to use to create teachpack?

I'm trying to create a teachpack for use with Intermediate Student Language.
I believe that I need to create a source file that uses the (provide ...)
form and I need to put it into a package.  I have two questions:

  - What, if anything, can I put into the info.rkt file to get my
    teachpack onto the teachpack menu (once the package is installed)?

  - What #lang should I use for the source code?  I'd like to stick
    to what I know, which is ISL, and in particular I'd like all
    arithmetic to be exact even in the presence of literals that contain
    decimal points.   But I also know I need to acquire a 'provide'
    form somehow...


Norman