gistfile1.txt

# Extend Mage_Catalog_Block_Product_View and override getJsonConfig as

    public function getJsonConfig($_product = null, $configurable_id = null)
    {
    	$_product = $_product? Mage::getModel('catalog/product')->load($_product->getId()) : $this->getProduct();
    	
        $config = array();
        if (!$this->hasOptions()) {
            return Mage::helper('core')->jsonEncode($config);
        }

        $_request = Mage::getSingleton('tax/calculation')->getRateRequest(false, false, false);
        $_request->setProductClassId($_product->getTaxClassId());
        $defaultTax = Mage::getSingleton('tax/calculation')->getRate($_request);

        $_request = Mage::getSingleton('tax/calculation')->getRateRequest();
        $_request->setProductClassId($_product->getTaxClassId());
        $currentTax = Mage::getSingleton('tax/calculation')->getRate($_request);

        $_regularPrice = $_product->getPrice();
        $_finalPrice = $_product->getFinalPrice();
        $_priceInclTax = Mage::helper('tax')->getPrice($_product, $_finalPrice, true);
        $_priceExclTax = Mage::helper('tax')->getPrice($_product, $_finalPrice);

        $config = array(
            'productId'           => $configurable_id? $configurable_id : $_product->getId(),
            'priceFormat'         => Mage::app()->getLocale()->getJsPriceFormat(),
            'includeTax'          => Mage::helper('tax')->priceIncludesTax() ? 'true' : 'false',
            'showIncludeTax'      => Mage::helper('tax')->displayPriceIncludingTax(),
            'showBothPrices'      => Mage::helper('tax')->displayBothPrices(),
            'productPrice'        => Mage::helper('core')->currency($_finalPrice, false, false),
            'productOldPrice'     => Mage::helper('core')->currency($_regularPrice, false, false),
            'skipCalculate'       => ($_priceExclTax != $_priceInclTax ? 0 : 1),
            'defaultTax'          => $defaultTax,
            'currentTax'          => $currentTax,
            'idSuffix'            => '_clone',
            'oldPlusDisposition'  => 0,
            'plusDisposition'     => 0,
            'oldMinusDisposition' => 0,
            'minusDisposition'    => 0,
        );

        $responseObject = new Varien_Object();
        Mage::dispatchEvent('catalog_product_view_config', array('response_object'=>$responseObject));
        if (is_array($responseObject->getAdditionalOptions())) {
            foreach ($responseObject->getAdditionalOptions() as $option=>$value) {
                $config[$option] = $value;
            }
        }
        return Mage::helper('core')->jsonEncode($config);
    }

# At the top of the Product view.phtml add
<script type="text/javascript">
    var selectedAssociatedOptionPrice = optionsPrice;
    <?php if($_product->isConfigurable()): ?>
    var associactedOptionsPrice = {};
    <?php
    	$_childProducts = $_product->getTypeInstance()->getUsedProducts(null, $_product);
    	foreach($_childProducts as $_childProduct):
    	?>associactedOptionsPrice.aPId<?php echo $_childProduct->getId(); ?> = new Product.OptionsPrice(<?php echo $this->getJsonConfig($_childProduct) ?>);
    <?php endforeach; ?>
    <?php endif; ?>
</script>

# rewrite your js function 'Product.Config.prototype.reloadPrice' in scp_product_extension.js to:
Product.Config.prototype.reloadPrice = function() {
    var childProductId = this.getMatchingSimpleProduct();
    var childProducts = this.config.childProducts;
    var usingZoomer = false;
    if(this.config.imageZoomer){
        usingZoomer = true;
    }
// LemonSkip Changes START:
	selectedAssociatedOptionPrice = optionsPrice;
    if (childProductId){
    	// replace optionsPrice for an associated product
    	if(associactedOptionsPrice.hasOwnProperty('aPId'+childProductId)){
    		selectedAssociatedOptionPrice = associactedOptionsPrice['aPId'+childProductId];
    	}
        var price = childProducts[childProductId]["price"];
        var finalPrice = childProducts[childProductId]["finalPrice"];
        selectedAssociatedOptionPrice.productPrice = finalPrice;
        selectedAssociatedOptionPrice.productOldPrice = price;
        selectedAssociatedOptionPrice.reload();
        selectedAssociatedOptionPrice.reloadPriceLabels(true);
        selectedAssociatedOptionPrice.updateSpecialPriceDisplay(price, finalPrice);
// LemonSkip Changes END:
        this.updateProductShortDescription(childProductId);
        this.updateProductDescription(childProductId);
        this.updateProductName(childProductId);
        this.updateProductAttributes(childProductId);
        this.updateFormProductId(childProductId);
        this.addParentProductIdToCartForm(this.config.productId);
        this.showCustomOptionsBlock(childProductId, this.config.productId);
        if (usingZoomer) {
            this.showFullImageDiv(childProductId, this.config.productId);
        }else{
            this.updateProductImage(childProductId);
        }

    } else {
        var cheapestPid = this.getProductIdOfCheapestProductInScope("finalPrice");
        //var mostExpensivePid = this.getProductIdOfMostExpensiveProductInScope("finalPrice");
        var price = childProducts[cheapestPid]["price"];
        var finalPrice = childProducts[cheapestPid]["finalPrice"];
        optionsPrice.productPrice = finalPrice;
        optionsPrice.productOldPrice = price;
        optionsPrice.reload();
        optionsPrice.reloadPriceLabels(false);
        optionsPrice.updateSpecialPriceDisplay(price, finalPrice);
        this.updateProductShortDescription(false);
        this.updateProductDescription(false);
        this.updateProductName(false);
        this.updateProductAttributes(false);
        this.showCustomOptionsBlock(false, false);
        if (usingZoomer) {
            this.showFullImageDiv(false, false);
        }else{
            this.updateProductImage(false);
        }
    }
};

# I did not change anything in scpajaxoptions.phtml as it always sent back an empty object!?!

# In scpoptions.phtml on line 130 ish I replaced it with
       selectedAssociatedOptionPrice.changePrice('options', price);
       selectedAssociatedOptionPrice.reload();

# Now the tax of a the selected child product is applied to the view! Nauice