Hi,

The Premier Support just gave me a solution.

I have to get the following aggregated result (SUM) from opportunities And copy it in a custom object (Quotation__c) field.

AggregateResult[] QuotedOps = [SELECT quotation__c, SUM(FeeProrated__c) FROM opportunity WHERE quotation__c =: quos
GROUP BY quotation__c];

Here are my quotation__c records:

List<Quotation__c> quotations = [SELECT Id, FeeTotal__c, CurrencyISOCode FROM quotation__c WHERE Id IN: quos];

I get the quotation currency ISO code:

for(Quotation__c quo: quotations){
    string quotationCurrency = quo.CurrencyIsoCode;

I get the conversion rate from my company default currency by querying the currencytype object:

    Double conversionRate = [SELECT conversionrate FROM currencytype WHERE isocode =: quotationCurrency LIMIT 1].conversionRate;

    for(AggregateResult ar: QuotedOps){
        qID = (Id)ar.get('quotation__c');
        if(quo.Id == qID){

Then to get the correct amount, I have to multiply the aggregated sum by the conversion rate to the quotation currency:

            quo.FeeTotal__c = (Decimal)ar.get('Total')*conversionRate;
        }
    }
}

I though that currency conversion was automatic, but it appears that you have to manage it in your code.

I hope this helps.