Add Currency Selector to WHMCS Custom Template

I have a Custom WHMCS Template, at "cart", appears the currency selector, with both of my currencies. But only at the begin, i mean without products or anything selected. But at DomainChecker, when adding domain to a Hosting product, Config product page, config domains, and also at Cart View with already products in it, the currency selector is Missing. English or Spanish. FTP Access