According to Telerik, you have to define the type and root of xml...
schema: {
type: 'xml',
data: '/logData/log',
model: {
fields: {
historyId: 'historyId/text()',
userId: 'userId/text()',
taskDate: 'taskDate/text()
}
}
},
Remove also the <?xml version="1.0" encoding="UTF-8"?> part from the string...