"Add another" popup with django-ajax-selects

Question

I try to use django-ajax-selects in a form used in a view (not in the admin). I sucessfully get the autocomplete field working (with lookup), but I don't know how to add the "+" button to add a new record.

My current code looks like:

-- models.py

class Address(models.Model):
    partner = models.ForeignKey(Partner, related_name='addresses', verbose_name=_('partner name'))
    contact_name = models.CharField(_('contact surname'), max_length=100, blank=True)
    contact_first_name = models.CharField(_('contact first name'), max_length=100, blank=True)

class PurchaseOrder(models.Model):
    order_number = models.CharField(_('order number'), max_length=100, blank=True,) 
    supplier = models.ForeignKey(Address, verbose_name=_('supplier'))

-- forms.py

class PurchaseOrderForm(ModelForm):
    supplier = AutoCompleteSelectField('address', required=True)
    class Meta:
        model = PurchaseOrder
        fields = ('supplier', 'order_number')

Now, I am supposed to subclass AjaxSelectAdmin or include the autoselect_fields_check_can_add hook in my admin's get_form() AjaxSelectAdmin from the official doc

def get_form(self, request, obj=None, **kwargs):
    form = super(AjaxSelectAdmin,self).get_form(request,obj,**kwargs)
    autoselect_fields_check_can_add(form,self.model,request.user)
    return form

but I have no idea where to add this... Can somebody point me in the right direction?