Problem using LabelFor Razor MVC 3 + C #

I have the following error in my View : when I pass @class="classe boot-strap" is not used, even passing View inside parameter @class it insists on using 'text-box single-line' , code snippets.

Code Razor :

 @Html.EditorFor(model => model.DataManutencao, new { @class = "span2 control-label" })

HTML debugger HTML code:

<input class="text-box single-line" data-val="true" data-val-date="The field Data Agendamento must be a date." data-val-required="Este campo é obrigatório!" id="DataManutencao" name="DataManutencao" type="datetime" value="01/01/0001">