I think you first need to update the ProductTemplateShortened.ascx file to include the tax rate in a hidden field (stick it next to the one that holds the price):
<asp:Literal ID="litMinTaxHidden" runat="server" Text='<%# Eval("MinTaxRate") %>' Visible="false" />
Then in the codebehind, need to update the price view calculation to deduct tax:
litPriceView.Text = CurrenciesBLL.FormatCurrencyPrice(Session("CUR_ID"), CDbl(litPriceHidden.Text) / (1 + (CDbl(litMinTaxHidden.Text) / 100)))