Recurring amount problem

[profcoder]

Hi,

I am selling product X with $40/month for example. But I have to sell it with Turkish Liras so I've updated CC Gateway "Convert To For Processing" option to TL. So it converts $40 to (current day's currency rate * 40) TL

When a customer buys the product, the recurring amounts becomes the amont above. However the currency rate changes rapidly in Turkey.

How to keep $40 as recurring amount while selling with Turkish Liras

Thanks.