Using FieldList and FormField

We have the following forms and we are trying to create list of GroupRoleForms for each group.

class FullNameMixIn():
    full_name = TextField(
        'Full name', [
            validators.required(message=u"Full name is required")
        ])

class GroupRoleForm(Form):
    group =BooleanField('Group', default=False)
    role = SelectField(
            'Role',choices=[
            ("none", "----------"), 
            ('approver', 'Approver'),
            ('editor', 'Editor')
            ])

class AdminEditUserForm(Form, FullNameMixIn):
    group_roles = FieldList(FormField(GroupRoleForm))

How can we create a AdminEditUserForm instance that contains a pre-populated list of GroupRoleForms?

At the moment we are trying to do it this way:

form = forms.AdminEditUserForm()
for group in  company.groups:
    group_role_form = forms.GroupRoleForm()
    group_role_form.group.label =  group.name
    group_role_form.group.name = group.id
    form.group_roles.append_entry(group_role_form)
return dict(edit_user_form = form )