[Avodah] charging ribis to a Jew / non-Jew

[Akiva Blum]

   Mikha'el Makovi:
 
>It would be interesting then, to do a heter iska with a gentile. The
   >Gemara offers that it is permissible to pay interest to a gentile,
   >just not charge, so perhaps no heter iska would be needed if he wanted
   >to charge you interest. That's fortunate, because it would certainly
   >be an interesting thing: go to a bank to take out a loan, and ask the
   >bank employee to sign an Aramaic document permitting you to pay him
   >interest.
   >
   >Anyone more expert on this issue than me?

And:
   > Now, on business matters, I see no problem -
   >and apparently Chazal didn't either, since they created the heter
   >iska. But notice that he heter iska is forbidden for personal
   >household type transactions - it seems to me that Chazal felt that
   >morally, it would be wrong to use a heter iska to permit interest for
   >necessary household goods. Only for non-necessary (i.e. business)
   >transactions did Chazal permit interest.
   >

Heter Iska is not a heter of chazal for ribis. Firstly, chazal didn't create it. It was formed in the centuries following. For that reason, I don't recall ever having seen one written in aramaic. They are written in hebrew, though any other language is just as good.
The way it works, bekitzur, is by restructuring the transaction from a loan to an investment. This is not a religious document, but a legal one. For it to be effective, it must have legal force. Therefore, wheras there are no problems contructing such an agreement with your local american bank, having a clerk sign on some paper would be meaningless if he is unauthorized.
Anyone can do this for any purpose. It just needs to be legally binding.

Akiva