What you need is on page 98.
Arrays overlap with normal variables: A(0) = A, A(1)=B,...A(25) =Z.
The DEFM statement increases the number of variables:
DEFM 76 gives you 102 variables (A-Z+76)
Now you can use A and B as variables, and C(0) to C(99) as an array.
That's what I needed. I wanted to run the benchmark on the 720P, but it was giving an error on the array, then on the DIM statement, etc. Without a manual, that was about as far as I could get. :-)
This is the reason, why I REMed the DIM in line 20 of the Basic version. Also many Sharps have a predefined array overlapping the variables A-Z as same the Casio do.