This feature is part of the Multi-Currency Add-On, which is an additional module for Big Business that supports transactions in foreign currencies.
The Misc. Bill tool does not support Foreign Currency entries. There simply isn't space for the Currency and Exchange Rate information necessary for each Bill.
This Solution provides an alternative for entering a Foreign Currency Bill without line items. (5965)
The Misc. Bill tool provides a quick way of entering Bills that do not have line items, just a dollar amount, and post by default to the Vendor's Expense Category. If you save a Misc. Bill and then open it, you will find that it opens as a regular Bill, with a "Misc. Bill" line item.
To enter a "Misc. Bill" for a Foreign Currency Vendor, use the regular Bill tool. Intead of choosing an Item on the first row of Line Items, simply enter a Qty of 1 and a Cost in the desired total amount.