ASP.NET MVC: Need help putting a form inside a boo

Question

I am having a heck of time trying to figure out how to put a form inside of a bootstrap modal. I think my problem is when I try and return something from the controller. But you may spot some other problem with how I'm doing this. Here's what I've got:

The Parent View:

<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
    <div class="modal-dialog modalAE" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                <h3><strong>Edit Account Profile - <span class="accountname"></span></strong></h3>
            </div>
            @using (Html.BeginForm("AccountProfileEdit", "Account", FormMethod.Post, new { id = "form-accountedit-appt", @class = "full-form" }))
            {
            <div class="modal-body">
                @Html.Partial("~/Views/Shared/_AccountProfileEdit.cshtml", new namespace.Models.AccountProfileEditViewModel())
            </div>
            <div class="modal-footer">
                <button type="submit" id="accountprofileedit-submit" name="accountprofileedit-submit" value="Edit Account" class="btn btn-primary" style="margin-left:5px;">Edit Account</button>
                <button type="button" class="btn btn-primary" data-dismiss="modal">Cancel</button>
            </div>
            }
        </div>
    </div>
</div>

The Partial View (slimmed down):

@model namespace.Models.AccountProfileEditViewModel  

@Html.CustomTextboxFor(model => model.Address)

The Partial View's Model (also slimmed down):

public class AccountProfileEditViewModel
{

    [Display(Name = "Address")]
    [Required()]
    [StringLength(200)]
    public string Address { get; set; }

    public AccountProfileEditViewModel() { }
}

The Partial View's Controller:

Note the question embedded in the code: WHAT DO I PUT HERE?

    [HttpPost]
    public ActionResult AccountProfileEdit([Bind]AccountProfileEditViewModel model)
    {

        if (Request.Form["accountprofileedit-submit"] != null)
        {
            if (ModelState.IsValid)
            {
                // logic to store form data in DB
            }
        }
        return PartialView(**WHAT DO I PUT HERE??**, model);
    }

No matter what I put here, it goes wrong. If I put the path to the partial view:

return PartialView("~/Views/Shared/_AccountProfileEdit.cshtml", model);

Then after the form is submitted, it just spits the html of the partial view onto the screen, totally out of context. But if I try this:

return PartialView("AccountProfileEdit", model);

I get an error: The partial view 'AccountProfileEdit' was not found or no view engine supports the searched locations.