Data structures in free prototypes?

OK, I'm sure this is obvious ... but I'm missing something.

I'm trying to define a procedure interface that has data structures as it's parameters.

dcl-pi *n;
dcl-ds p1 qualified;
parm1 char (10);
parm2 char (10);
parm3 char (1);
end-ds;
dcl-ds p2 qualified;
parm4 char (10);
parm5 char (10);
end-ds;
end-pi;

When I compile, I get this error on the dcl-pi: RNF0202: THE END-PI IS MISSING FOR A GROUP CONTAINING FREE-FORM; END-PI IS ASSUMED.

Is this even possible?

Thanks!

david