How to use Multiple Unit Cargo Wagons from 2cc TarinSet?

[Pingu79]

Hi everybody,
I'm playing with "2cc Trains in NML 3.0" NewGRF, in the train depot-buy new vehicles windows there are 2 wagon called "Multiple Unit Wagon" (bot powered and unpowered version) with description "This generic wagons can ONLY be used with passenger MUs.." (even if they works also with mail and valuables) that I can use with EMU like TGV, but there are also "Multiple Unit Cargo Wagons" (also here powered and unpowered version) wich says "This generic wagons can ONLY be used with cargo MUs..." but no EMUs o DMUs available seems to be usable. I can attach them only to normal locomotives, but (as other MUs wagon) won't work as desiderd: thet don't take appropriate graphic, cargo capacity is limited to 1, and so on...
So, how to use them?

Thanks

P.S.
Even if Multiple Unit Wagons can refit to passenger/mail/valuables in depot refit at station (in train's order list) is grayed out. Is it a bug? Is is a not yet implemented feature or simply not desiderd?

[Emperor Jake]

The MU Cargo Wagon is only for use with the DB 691 CargoSprinter. Other cargo MUs were planned but we never finished drawing them unfortunatley.

Even if Multiple Unit Wagons can refit to passenger/mail/valuables in depot refit at station (in train's order list) is grayed out. Is it a bug? Is is a not yet implemented feature or simply not desiderd?

Station refitting needs to be specifically enabled by the code. It's not enabled for the MUs because it would result in passenger wagons magically losing their windows as they become refitted to mail