Enables the creation of a savings account variant that supports multiple currencies. This allows a single account to hold balances in multiple currencies simultaneously.

How it works:

• Specify a productId that references a multi-currency product
• The account will automatically support all currencies configured in that product
• Each supported currency will have its own sub-account within the main account
• Clients can deposit, withdraw, and hold balances in any of the supported currencies

Prerequisites:

1. A client must be established and active
2. A multi-currency product must be created and configured with the desired currencies

Note: This uses the same endpoint as the standard Create & Activate Account API, but with a multi-currency product ID.