Saved search on an encrypted field

Is there any way to return a saved search on a netsuite encrypted field?  We do a lot of business on a paticular corporate credit card issued by one particular bank.  All of these credit card numbers start with the bank's issued first 6 digits.  We have been trying to find a way to search sales orders that were paid for with one of these cards starting with the same 6 bank code digits.  Does anyone know of a way to search for these transactions?

I tried the following:
Formula (Text) starts with 471586 DECODE('471586%', Credit Card Number, cardnum [, search, result ]...[, default ]){cardnum}