Here is a small job which will explain how to add a map object to the sysPickList form. After executing the job you'll observe something like this

static void SysPickList_Map(Args _args)

{

    Map     s = new Map(Types::Integer, Types::String);

    Object  formRun;

    ;

    //Add values to the set

    s.insert(1, 'Santosh.R');

    s.insert(2, 'Chaitanya G.S.S');

    s.insert(3, 'Sampath.B');

    s.insert(4, 'Madan.T');

    s.insert(5, 'Chaitanya.P');

    s.insert(6, 'Veeresh.J');

    s.insert(7, 'Naveen');

    _args = new Args(formstr(SysPick));

    _args.parmObject(s);

    formRun = classfactory.formRunClass(_args);

    formRun.init();

    formRun.run();

    // Returns the sysPick Caption.

    formRun.setCaption('Set PickList');

    formRun.wait();

}

For any further reference try to research the Global class & function in AX which explains how can the sysPick be used.