Convert ByteArray to Array?

I have a ByteArray (returned from loading some data through a URLLoader), and I want to convert it to an Array. The reason is, I need to pass the Array to through ExternalInterface to the Javascript layer. If I pass an Array through, Flash correctly handles this. But if I pass a ByteArray through, no such luck.

I know I can just loop through the ByteArray, and readByte() it into a regular Array. But if the ByteArray is large, this seems like a furstratingly inefficient way of getting the data out.

Any ideas or clever ways to get the byte data from the ByteArray into an array, that can then be passed to javascript?