Looks like I can't do it. As soon as I put the little by @ sign in front of a parameter the form gives me a syntax error.
That is if the init of "myform" start with

LPARAMETERS ra_array

and my app has the following commands:

DIME la_array[2]
la_array[1]="A"
la_array[2]="B"
DO FORM MYFORM WITH @la_array

I get a response "syntax error"

Work arounds of the top of my head include declaring the array privates (ugh) so it does not have to be passed as a parameter, or creating a cursor that will be visible to the form.

However, maybe there is some simple way of passing an array as a true parameter to a form. If anyone knows of one...