I wrote to the specified address and this is their response:
Dear Dusty
We are not able to support the new Bitcoin ISO 4217 currency code, based on the following:
1. The currency code is not linked to any country code.
2. The currency code is considered a 'private currency' and not used for tender in any country.
3. There will be no international payments denominated in Bitcoin therefore an ISO currency code for the Bitcoin is not applicable.
4. The Institution responsible for the Bitcoin does not appear to be recognized internationally or have any official status. Neither Reuters or Bloomberg provides market data related to its use.
I would like to discuss each point to understand if this is debatable (I think it is).
For example:
1) Is it really necessary? For example: did the Euro have a iso code before being linked to any country code? Is "the world" a country where BTC can be linked?
2) Is that a legal tender they refer to? What defines "tender" otherwise?
3) it seems to me that every bitcoin transaction can be international by definition, and we have plenty of examples for that
4) that would be certainly very hard, but should that really be necessary?