Custom currency in Drupal Commerce Shopping cart summary views
I manage to do this using Views PHP module. The variable $results contains the array of all the data. 

For "Shopping cart form" and "Shopping cart summary" view you have to add to footer this to the output value of Global: PHP: 

&lt;?php 
$amount = 0;
foreach ($results  as $result) {
$amount = $result-&gt;field_commerce_total[0]['raw']['amount'] + $amount;
}
$converta = commerce_multicurrency_conversion($amount, 'HRK', 'GBP');
$formatcu = commerce_currency_format($converta, 'GBP');
echo $formatcu;
?&gt;


To the "Commerce add to cart confirmation" you haw to ad to fields Global: PHP output code: 

&lt;?php
$amount = $data-&gt;field_commerce_total[0]['raw']['amount'];
$converta = commerce_multicurrency_conversion($amount, 'HRK', 'GBP');
$formatcu = commerce_currency_format($converta, 'GBP');
echo $formatcu; 
?&gt;