ASP.Net MVC File uploading ViewModel Binding

Question

So I'm fairly new to ASP.net MVC and have been trying to make a fileuploader, but I can't seem to get my uploaded file bound to my viewmodel. I'm trying to apply validation to the uploaded file through my viewmodel which should be doable.

My code:

View:

<div id = "PDFForm">          
@using (Ajax.BeginForm("Upload", "Home", FormMethod.Post,
                        new AjaxOptions
                        {
                            InsertionMode = InsertionMode.Replace,
                            UpdateTargetId = "PDFForm",                          
                        },
                        new { id = "UploadForm", enctype = "multipart/form-data" }))
{
    <input type="file" name="Cover" id="Cover" />
    <input type="submit" value="Upload"/>
}
</div> 

ViewModel:

public class UploadVM
{    
    [Required]        
    public HttpPostedFileBase Cover { get; set; }
}

Controlller action:

public ActionResult Upload(UploadVM model)
{
    if(ModelState.IsValid() && model.Cover !=null)
    {
        //do things and return a response view
    }
    else
    {
        //return to form
    }
}

I've googled around for tutorials and they seem to be able to bind the uploaded file to the viewmodel by using:

enctype = "multipart/form-data"

I can't seem to get it working so I thought you guys might be able to help me out or push me in the right direction.

Thanks in advance!

Edit: I've tried it with HTML.BeginForm() too but that doesn't seem to work either