Using the attribute render method

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I am creating a block that will pull out a list of, let's say, pages and I want this block to list attributes that are of a select box type so you can filter based on that type. The reason I say that these are "mypages" are because they are infact a list of items that use a the built in attributes model, but are not in fact pages.

So I have written a method in the block's controller that returns all the select type attributes for the pages:

public function getSelectAttributes()
    {
        Loader::model('attribute/categories/mypages');
        $atkeys = array();
        $attributeKeys = MypagesAttributeKey::getList();
        if (is_array($attributeKeys)) {
            foreach($attributeKeys as $key) {
                if ($key->atHandle === 'select') {
                    $atkeys[] = $key;
                }
            }
            return $atkeys;
        }
        return false;
    }


And bring them through to the add/edit block form like so:

$selectAttr = $this->controller->getSelectAttributes();
if (is_array($selectAttr)) { 
    ?>
    <div class="ccm-block-field-group">
    <h4><?php echo t('Filter Attributes')?></h4><br/>
    <?php
    foreach ($selectAttr as $attr) {
        if (is_object($attr)) {
            ?>
            <div class="clearfix">
                <div class="input">   
                    <?php
                    $attr->render('form', $v, false);
                    ?>
                </div>


Now, when the form is submitted I write to the database table for the block the bID etc and also to another database table to remember what key and values are required for the filter.

btMypagesListFilter:
bID  akID  avID
1    2     1
2    5     1
3    2     2
4    5     2


My question is, when I am editing the block I want the drop down for the select boxes to preselect the chosen filter, so I somehow have to create a value object($v) (?) and pass it to the render method:

$attr->render('form', $v, false);


How do I create this object from the information in btMypagesListFilter ?

Hope I am clear enough. Any help is appreciated.