Fuel cells on the Strom must be plumbed into the factory tank, usually by adding a fitting to the fuel pump mounting plate. This is so because the fuel pump is mounted inside the fuel tank. The fuel line siamesing trick only works on bikes with externally mounted fuel pumps or gravity fed carbs.
I have used that technique on my Royal Star Venture, but on my DL1000 I am modifying the pump mounting plate. Also, I have mounted my fuel cell on a rack above the rear portion of the seat, making the bike a solo ride. This is the same method I used on the Venture, although in that case I was able to remove the rear seat to mount the tank as low as possible.
This mounting position allows me to retain the topcase in normal position and provides better weight balancing, with the fuel centrally located. As well, the fuel valve is within easy reach.
The most noticeable difference to me, is that on the Strom, I will have to drain the main tank first, instead of fuel cell first as I do on the Venture, because of the fuel pump location. A minor annoyance, but it is more time with the load mounted high.