IMO, it's only posible as written above, load the file to sampler put the left and right locator correctly and then export as (or how it is,,in Reason :)

The Refill packer is for creating refill, not reversely. U can creat your own patches and refills,. There are some known problems while moving the refill between Pc and Mac platforms,. It's something like all aiff files are changing to aifc, which is compressed format of aif, and Reason can't recognize it.

There is some tool for converting these files, it's File Buddy or something like this.