You can add a custom component(AnchorCustomComponent) Esri map, as I have done in google maps
This is the google api flash code:
var options:MarkerOptions = new MarkerOptions();
var anchor:AnchorCustomComponent = new AnchorCustomComponent();
anchor.colorcom = 0x3FA9F5;
anchor.idcom = ruteadoresCollection[value].idRuteador;
anchor.lblNum.text = "R-"+ruteadoresCollection[value].idRuteador;
anchor.currentState = "Normal";
options.icon = anchor;
options.draggable = false;