ReaderControl.config.ui.hideControlBar = true;
$(document).on('documentLoaded', function () {
var signatureTool = readerControl.toolModeMap['AnnotationCreateSignature'];
//This will catch the signature when it is added as the default
$(signatureTool ).on('saveDefault', function(event, paths){
yourFunctionToSaveToServer(paths);
});
var signatureFromServer = yourFunctionToRetrieveFromServer();
signatureTool.initDefaultSignature(signatureFromServer);
});