I finally got around to making a splitter for the power and most. I had to do this because my most bus was full. I purchased a cut off Sirius power/fiber plug from ebay. Next I purchased a .3 meter piece of fiber from ebay (orange in the pics) which shipped from China. The power/fiber plug is actually 3 plugs, power, fiber and a 3rd connector that the first 2 plug into so I was unsure if the ebay most splitters would work.
The fiber is in serial. So I took the fiber piece out of port 2 on the original plug and put it into port 2 of the new plug. I then used the orange jumper to go from pin 2 on original to pin 1 on new. Now IBOC and Sirius can both be seen on the bus.
I got the fiber here
Most Fiber Optic Optical Cable Pin to Pin Contact 1M BMW Mercedes Audi Porsche | eBay Just ask the seller for a shorter version if wanted.