I figured it out!

The key was this small bit of code, which passes the, "newValue" variable to the sysparm_state variable.

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }
    var ga = new GlideAjax("ASHNUserDetailsUtil");
    ga.addParam("sysparm_name", "user_info");
    ga.addParam("sysparm_state", newValue);
    ga.getXML(ajaxResponse);

Catalog Client Script

Script Inlucde: Client callable