Not able to change Currency for Service Tax on Imported Standalone AP invoices

Hi,

We are creating standalone AP invoice for imported services and need to apply service tax on such invoices along with reverse charge. The invoice is created with invoice currency EURO/USD.

The Update Currency flag is set to Yes on tax code definition. However, when we apply the Reverse Charge Service Tax on this invoice, the currency field is greyed out and we are not able to change the currency to INR. Following are the steps to reproduce-

1. Create tax codes for normal Service taxes and reverse charge services taxes with update currency flag = Yes

2. Create Tax category

3. Create AP invoice in EURO currency, enter line and distribution informations.