UR28M 5.1 surround setup via usb

I want to hook up my UR28M to my pc via usb. and then be able to play movies and stuff in 5.1 surround. Since the device has 6 analog outputs i can connect all the speakers BUT. If i play a file in 5.1 channels i only hear my front speakers.
I configured my setup to use the A-C channels independent and routed A to mix1, B to mix2 and C to mix 3 (as suggested in the forums). I think the problem lies in that windows (10) does not see the interface as a 6 channel device and only sends it stereo sound.

Is it even possible do have 5.1 surround? if yes how, if no what interface does have this option (below 400 Eur. preferebly)

My setup:
front 2 JBL LSR 305 studio monitors
Rear creative gigaworks t40
Center Seperate amplifier magnat needle
Sub Energy esw 8

// side question is it possible to use multiple 2 channel Interfaces to make 5.1 work?