gets a Magento parent product url with hash to pre-select configurable product option

gistfile1.php

function getProductUrlWithAttributes($product, $storeId) {
  
  $url = $product->setStoreId($storeId)->getProductUrl();
  $urlHash = array();
  $parentIds = Mage::getModel('catalog/product_type_configurable')->getParentIdsByChild($product->getId());
  
  if(isset($parentIds[0])) {
  
    $parent = Mage::getModel('catalog/product')->load($parentIds[0]);
    $url = $parent->setStoreId($storeId)->getProductUrl();
    $attrs = $parent->getTypeInstance(true)->getConfigurableAttributes($parent);
    
    foreach ($attrs as $attribute) {
      $productAttribute   = $attribute->getProductAttribute();
      $productAttributeId = $productAttribute->getId();
    
      if($attributeValue = $product->getData($productAttribute->getAttributeCode())) {
        $urlHash[$productAttributeId] = $attributeValue;
      }
    }
  } 

  if(count($urlHash) > 0) {
    $url .= '#'.http_build_query($urlHash, null, ',');
  }

  return substr($url, 0, 2000);
}

Suppose the attribute id is known and is "my_attr_sizes"? After that I loop through the child products collection to build the URL. I would then have something like $product_url + # + $attr_id + = + $attr_id_of_product_attr_value ==> How could I do this?