You can try handling AddedNewItem event of RadDataForm and set the values you want to be predefined:
private void DataForm1_AddedNewItem(object sender, AddedNewItemEventArgs e)
(this.DataForm1.CurrentItem as Club).Name = "NewName";
In you want to perform this operation only in your ViewModel, you can bind CurrentItem property of RadDataForm to a one in this ViewModel, create a new command that will add an item with default values and set this command to be the one for your button.
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