Exercise solution:
The append function

  (define (my-next-append lst1 lst2)
    (my-next-append-1 (reverse lst1) lst2 lst2))

  (define (my-next-append-1 lst1 lst2 res)
    (cond ((null? lst1) res)
          (else (my-next-append-1 
                  (cdr lst1) lst2 (cons (car lst1) res)))))

In order to compensate for the 'reversing problem' I pass lst1 in reversed form to the iterative function my-next-append-1.

Also I pass the list lst2 as the initial value of res. This is crucial in order to get the lists appended at all.