[racket] keybinding help needed

I really like DrRacket text mode, which I've been using extensively
for a few days.  I tried it a few years ago and it crashed constantly,
but I find it completely stable now, and it's very usable, a tolerable
alternative to Emacs for working on PCs.

But I would like some help making some new keybindings.   The 
DrRacket: Programming Environment manual has only one example:

3.3.8 Defining Custom Shortcuts
(keybinding "c:a" (lambda (editor evt) (send editor insert "!")))

Maybe if I'd built DrRacket on Linux, I'd see more examples, but I'm
missing some necessary libraries at present.  I just want to bind some
keys, maybe function keys, to common functions like save, cut, copy &
paste. 

It would also be nice to change the comment character ; to %, as I'm
editing Latex files.

Some bio info: 
My 11-yr old son is learning Scheme, and he loves DrRacket, in which
he found all the 1224 twin primes under 100K---largest (99989 99991).

I published a paper a year ago

Combinatorial proofs of the Lambda algebra basis and EHP
      sequence.  
    Proc.  American Mathematical Society 137, 2471--2482 (2009) 

Five years ago I helped Shriram fix a free/bound variable substitution
problem in excellent book PLAI.