How can i create multiselect lookup?

define("ContactPageV2", [], function() {
	return {
		entitySchemaName: "Contact",
		attributes: {
 
		},
		modules: /**SCHEMA_MODULES*/{}/**SCHEMA_MODULES*/,
		details: /**SCHEMA_DETAILS*/{}/**SCHEMA_DETAILS*/,
		businessRules: /**SCHEMA_BUSINESS_RULES*/{}/**SCHEMA_BUSINESS_RULES*/,
		methods: {
		},
		dataModels: /**SCHEMA_DATA_MODELS*/{}/**SCHEMA_DATA_MODELS*/,
		diff: /**SCHEMA_DIFF*/[
			{
				"operation": "insert",
				"name": "hasForeignTrade",
				"values": {
					"click": "getLookupConfig",
					"layout": {
						"colSpan": 12,
						"rowSpan": 1,
						"column": 0,
						"row": 2,
						"layoutName": "ContactGeneralInfoBlock"
					},
					"bindTo": "UsrHasForeignTrade",
					"labelConfig": {
						"caption": {
							"bindTo": "Resources.Strings.hasForeignTrade"
						}
					},
					"enabled": true,
					"contentType": "Terrasoft.core.enums.ContentType.LOOKUP"
				},
				"parentName": "ContactGeneralInfoBlock",
				"propertyName": "items",
				"index": 4
			},
 
		]/**SCHEMA_DIFF*/
	};
});

Hello,

How can i make this lookup multiselect?