Resco CRM - assign value to field from field from another entity

function onCustomerChanged(entityForm) {
if (entityForm.context.changedItem == "customerid") {
		accountId = entityForm.entity.properties.customerid.id;
		if(entityForm.entity.properties.avanade_wholesaleraccountno == null)
		{
			var account = new MobileCRM.FetchXml.Entity("account");
			account.addAttribute("avanade_wholesaleraccountno");
			var filter = new MobileCRM.FetchXml.Filter();
			filter.where("accountid", "eq", accountId);
			account.filter = filter;
			var fetch = new MobileCRM.FetchXml.Fetch(account);

			var props = entityForm.entity.properties;


			fetch.execute("Array", function (result) {
				if (result && result.length > 0)		{
					alert(result[0]);
                    props.asd_wholesaleraccountno = result[0];
                    alert(props.asd_wholesaleraccountno);
				}
			}, function (err) {
				MobileCRM.bridge.alert("Error during get WS account number info: " + err);
			}, entityForm);
		}
	}
}