Hi!

If someone is interested, here is the code for activating GA Ecommerce functionality. It is for v1.9, I don't know if applies for other, I guess for 2.x it doesn't.

Just Copy/Paste it to "CheckoutCompleted.ascx" (of course only the code between <script>...</script> is important and yes, change "UA-XXXXXX-X" with your GA ID):

<%@ Control Language="C#" AutoEventWireup="true" Inherits="NopSolutions.NopCommerce.Web.Modules.CheckoutCompletedControl"
    CodeBehind="CheckoutCompleted.ascx.cs" %>
<%@ Register TagPrefix="nopCommerce" TagName="OrderDetails" Src="~/Modules/OrderDetails.ascx" %>

<script type="text/javascript">

    var _gaq = _gaq || [];
    _gaq.push(['_setAccount', 'UA-XXXXXX-X']);
    _gaq.push(['_trackPageview']);
    _gaq.push(['_addTrans',
    '<%= NopContext.Current.User.Orders[0].OrderId.ToString() %>',           // order ID - required
    'Actionmama',  // affiliation or store name
    '<%= NopContext.Current.User.Orders[0].OrderTotal.ToString() %>',          // total - required
    '<%= NopContext.Current.User.Orders[0].OrderTax.ToString() %>',           // tax
    '<%= NopContext.Current.User.Orders[0].OrderShippingInclTax.ToString() %>',              // shipping
    '<%= NopContext.Current.User.Orders[0].ShippingCity.ToString() %>',       // city
    '<%= NopContext.Current.User.Orders[0].ShippingStateProvince.ToString() %>',     // state or province
    '<%= NopContext.Current.User.Orders[0].ShippingCountry.ToString() %>'             // country
  ]);

    // add item might be called for every item in the shopping cart
    // where your ecommerce engine loops through each item in the cart and
    // prints out _addItem for each
    <% foreach (NopSolutions.NopCommerce.BusinessLogic.Orders.OrderProductVariant item in NopContext.Current.User.Orders[0].OrderProductVariants) { %>
    _gaq.push(['_addItem',
    '<%= NopContext.Current.User.Orders[0].OrderId.ToString() %>',           // order ID - required
    '<%= item.ProductVariant.SKU.ToString() %>',           // SKU/code - required
    '<%= item.ProductVariant.Product.Name.ToString() %>',        // product name
    '<%= item.ProductVariant.Product.ProductCategories[0].Category.Name.ToString() %>',   // category or variation
    '<%= item.UnitPriceInclTax.ToString() %>',          // unit price - required
    '<%= item.Quantity.ToString() %>'               // quantity - required
  ]);
  <% } %>
    _gaq.push(['_trackTrans']); //submits transaction to the Analytics servers

    (function () {
        var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
        ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
        var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
    })();

</script>

<div class="checkout-data">
    <div class="order-completed">
        <div class="body">
            <b>
                <%=GetLocaleResourceString("Checkout.YourOrderHasBeenSuccessfullyProcessed")%></b>
            <p>
                <%=GetLocaleResourceString("Checkout.OrderNumber")%>:
                <asp:Label runat="server" ID="lblOrderNumber" />
            </p>
            <p>
                <asp:HyperLink runat="server" ID="hlOrderDetails" Text="<% $NopResources:Checkout.OrderCompleted.Details %>" />
            </p>
        </div>
        <div class="clear">
        </div>
        <div class="select-button">
            <asp:Button runat="server" ID="btnContinue" Text="<% $NopResources:Checkout.Continue %>"
                OnClick="btnContinue_Click" CssClass="orderprocessedcontinuebutton" />
        </div>
    </div>
</div>

Hope it helps!

Cheers, Matic