Hi BlueRosey
When you load the file containing the style, it will place the style in Composer A.
To copy that style from Composer A to Custom Style use Composer>Custom Style Copy (make sure you choose the Direction from Memory Bank A to Custom Style (Number) - that's it. However, make sure you have saved your existing Custom Style Banks before copying new styles into the Custom Style positions. You can use this method to copy different styles into the Custom Rhythms.
John